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TLVs Threshold Limit Values for Physical Agents in the Work Environment Adopted by ACGIH for 1984-85 AP00055758 1983*84 TLV PHYSICAL AGENTS COMMITTEE Herbert H. Jones (Retired) --Chair Peter A. Breysse. University of Washington Thomas Cummings (Retired) Irving H. Davis. Michigan Dept, of Public Health Zory R. Glaser, Ph.D., National Center for Devices & Radiological Heaith/FDA Allan P. He ins, Ph.D., OSHA --Secrefary LCDR Richard Johnson, USN Edward J. Largent (Retired) John C. Mitchell, USAF Anthony M. Muc, Ph.D., Ontario Ministry of Labour William E. Murray, NIOSH Wordia H. Parr, Ph.D. (Retired) David H. Sliney, USAEHA COL Robert T. Wangemann. USA Thomas K. Wilkinson, National institutes of Health CONSULTANTS Gerald V, Coles Donald E.Wasserman This book is fully protected by copyright and no part of it may be reproduced in any form, by print, photoprint, microfilm, or any other means without written permission. Any comments or questions regarding these limits, or requests to reprint should be addressed to: Executive Secretary American Conference of Governmental Industrial Hygienists 6500 Glenway Ave., Bldg. D-5 Cincinnati, OH 45211: (513)661-7881 66 PREFACE PHYSICAL AGENTS These threshold limit values refer to levels of phys ical agents and represent conditions under which it is believed that nearly all workers may be repeatedly ex posed day after day without adverse effect. Because of wide variations in individual susceptibility, expo sure of an occasional individual at. or even below, the threshold limit may not prevent annoyance, aggrava tion of a pre-existing condition, or physiological dam age. These threshold limits are based on the best avail able information from industrial experience, from ex perimental human and animal studies, and when pos sible, from a combination of the three. These limits are intended for use in the practice of industrial hygiene and should be interpreted and ap plied only by a person trained in this discipline. They are not intended for use. or for modification for use. (1) in the evaluation or control of the levels of physi cal agents in the community. (2) as proof or disproof of an existing physical disability, or (3) for adoption by countries whose working conditions differ from those in the United States of America. These values are reviewed annually by the Com mittee on Threshold Limits for Physical Agents lor re visions or additions, as further information becomes available. Notice of Intent--At the beginning of each year, proposed actions of the Committee for the forthcom ing year are issued in the form of a "Notice of Intent." This notice provides not only an opportunity for com ment but solicits suggestions of physical agents to be added to the list. The suggestions should be ac companied by substantiating evidence. As Legislative Code -- The Conference recognizes that the Threshold Limit Values may be adopted in legislative codes and regulations. If so used, the in tent of the concepts contained in the Preface should be maintained and provisions should be made to keep the list current. 67 1 AP00055759 THRESHOLD LIMIT values HEAT STRESS These Threshold Limit Values refer to . conditions under which it is belie that`no*tre* workers may be repeatedly exposed witho,,? t y alt health sheets. The TLVs shown in Table i a a<L8|*fc on the; assumption that nearly all acciimati?*8w clothed workers with adequate water and salt* ful|y should be able to function effectively under thtfMake working conditions without exceeding a riI!?9L1Veri temperature of 33*0."'41 ^ body Since measurement of deep body tempest impractical for monitoring the wooers' heat loan15 '9 measurement of environmental factors js rsrt.thB which most nearly correlate with deep body tern 0,3 ture and other physiological responses to hear present time Wet Bulb Globe Temperature inn 6 (WBGT) is the simplest and most suitable techrii to measure the environmental factors, WBGT va, are calculated by the following equations: ues 1 Outdoors with solar load: WBGT = 0.7 NWB + 0.2 GT + 0.1 OB 2 Indoors or Outdoors with no solar load' WBGT * 0.7 NWB +0.3 GT where: WBGT =* Wet Bulb Globe Temperature index NWB - Natural Wet-Bulb Temperature 06 = Dry-Bulb Temperature GT * Globe Temperature The determination of WBGT requires the use of a black globe thermometer, a natural (static) wet-bulb thermometer, and a dry-bulb thermometer. Higher heat exposures than shown in Table 1 are permissible if the workers have been undergoing medical surveillance and if has been established that they are more tolerant to work in heat than the average worker. Workers should not be permitted to continue their work when their deep body tempera ture exceeds 38.0C. EVALUATION ANQ CONTROL I. Measurement of the Environment The instruments required are a dry-bulb, a natural wet-bulb, a globe thermometer, and a stand. The 68 -....... - xl ! : j .l , TABLE T sib!e Heat Exposire Threshold Limit Values perfP Values are given in C. WBGT) Rest Regimen Work Load Light Moderate Heavy 30.0 26,7 25.0 S Rest! Each hour 75% Rest Sch hour 30.6 28.0 25.9 31.4 29.4 27.9 32.2 31.1 30.0 I i measurement of the environmental factors shall be performed as follows: A The range of the dry and the natural we? bulb ther mometer shall be -5C to 50"C with an accuracy ot -'-0 5aC- The dry bulb thermometer must be shielded from the sun and the other radiant surfaces of the en vironment without restricting the airflow around the bulb- The wick of the natural wet-bulb thermometer shall be ksp* wst with disti,,eci water for at least 1/2 hour before the temperature reading is made. It is not enough to immerse the other end of the wick into a reservoir of distilled water and wait until the whole wick becomes wet by capillarity. The wick shall be wetted by direct application of water from a syringe 1/2 hour before each reading. The wick shall extend over the bulb of the thermometer, covering the stem about one additional bulb length. The wick should always be clean and new wicks should be washed be fore using. B. A globe thermometer, consisting of a IS cm. (6inch) diameter hollow copper sphere painted on the outside with a matte black finish or equivalent, shall be used. The bulb or sensor of a thermometer (range -5a<7 to 1Q0C with an accuracy ot Q.$G) must be fixed in the center of the sphere. The globe thermom eter shall be exposed at least 25 minutes before it is read. !.-<C AP00055760 C. A stand Shall be used to suspend the three ther mometers SO that they do not restrict free air flow around the bulbs;, and the wet-bulb and globe ther mometer are not shaded. D. it is permissible to use any other type of tempera ture sensor that gives identical reading as that of a mercury thermometer under the same conditions. E. The thermometers must be so placed that the readings are representative of the condition where the men work or rest, respectively. The methodology outlined above is more fully ex plained by Minard,'*-41 I!. Work Load Categories Heat produced by the body and the environmental heat together determine the total heat load. There fore, if work is to be performed under hot environ mental conditions, the workload category of each job 25 LfCEHQ OX'nuOUS ?:ii, km n*r (Mi toms* t 2'lt. . rt% c*r ttcx not* 20 100 200 300 400 500 kcai/hr 400 900 1200 1500 2000 Btu/hr Rote of Work 40 O 3) Figure 1 -- Permissible Heat Exposure Threshold limit Value 70 TABLE 2 Assessment of Work Load'5" Average values of metabolic rate during different acnvibes. Body position and movement Sitting Standing Walking Walking up hill kcal/min 0.3 0.6 2.0-3.0 add 0.8 per meter (yard).rise B. Type of Work Average Range kcal/min kcal/min Hand work Work with one arm Work with both arms Work with body light heavy light heavy light heavy light moderate heavy very heavy 0.4 0.9 1.0 1.8 1.5 2.5 3.5 5.0 7.0 9.0 0.2-1.2 0.7-2.5 1.0-3.5 2.515.0 1 shall be established and the heat exposure limit perti nent to the work toad evaluated against the applica ble standard in order to protect the worker from ex posure beyond the permissible limit. A. The work load category may be established by ranking each job into light, medium, and heayy cate gories on the basis of type of operation. Where the work load is ranked into one of said three categories. (1) light work (up to 200 kcal/hr or 000 3tu/hr): e.g,, sitting or standing to control machines, perform ing light hand or arm work, 71 AP00055761 TABLE 3 Activity Examples'''' Light hand work: writing, hand knitting Heavy hand work: typewriting Heavy work with one arm: hammering in nails (shoe maker. upholsterer} Light work with two arms: tiling metal, planing wood, raking of a garden Moderate work with the body: cleaning a floor, beating a carpet Heavy work with the body: railroad track laying, digging, barking trees Sample Calculation Assembly line work using a heavy hand tool. A. Walking along 2.0 kcal/min B. intermediate value between heavy work with two arms and light work with the body 3.0kcai/min C. Add for basal metabolism 5.0 kcal/min 1.0 kcal/min Total 6.0 kcal/min (2) moderate work (200-350 kcaf/hr or 000-1400 Stu/hr): e.g., walking about with moderate lifting and pushing, (3) heavy work (350-S00 kcal/hr or 1400-2000 Btu/hr): e.g., pick and shovel work. the permissible heat exposure limit for that work load shall be determined from Table 1. B. The ranking of the job may be performed either by measuring the worker's metabolic rate while perform ing his job or by estimating his metabolic rate with the use of Tables 2 and 3- Additional tables available in the literature'*'*' may be utilized also. When this method is used the permissible heat exposure limit can be determined by Figure 1. 72 HI. Work-Rest Regimen The permissible exposure limits specified in Table 1 and Figure 1 are based on the assumption that the WBGT value of the resting place is the same or very close to trial of the work place. Where the WBGT of the work area is different from that of the rest area a time-weighted average value should be used for bath environmental and metabolic heat. When timeweighted average values are used the appropriate curve on Figure 1 is the solid line labeled "continu ous." The time-weighted average metabolic rate (M) shall be determined by the equation: , .. Mi xti + Mj x b + . - - . + M,, x L, Av-M ='+1.----------------- where Mi, M2 . . . and ML are estimated or measured metabolic rates for the various activities and rest periods of the worker during the time periods ti, I2 . .. and t, {in minutes) as determined by a time study. The time-weighted average WBGT shall be deter mined by the equation: Av. W8GT = WBGT! x ti + WBGT2 x ta + .. . + WBGT, x t,, ti + ta + . . . +1, where WBGTi, WBGTj . .. and WBGT, are calculated values of WBGT for the various work and rest occu pied during total time periods ti. U - . . and t, are the elapsed times in minutes spent in the corresponding areas which are determined by a time study. Where exposure to hot environmental conditions is continu ous for several hours or the entire work day, the timeweighted averages shall be calculated as hourly timeweighted average i.e., ti+t2+.., + ^= 60 minutes. Where the exposure is intermittent, the time-weighted averages shall be calculated as two-hour time-weight ed averages, i.e., t( + t* + ... + t, = 120 minutes. The permissible exposure limits for continuous work are applicable where there Is a work-rest regi men of a 5-day work week and an 8-hour work day with a short morning and afternoon break (approxi mately 15 minutes) and a longer lunch break (approx imately 30 minutes). Higher exposure limits are per mitted if additional resting time is allowed. All breaks, including unscheduled pauses and administrative or operational waiting periods during work may be 73 AP00055762 counted as rest time when additional rest allowance must be given because of high environmental temper atures. IV. Wafer and Salt Supplementation During the hot season or when the worker is ex posed to artificially generated heat, drinking water shall be made available to the workers in such a way that they are stimulated to frequently drink small amounts, i.e., one cup every 15-20 minutes (about 150 ml or 1/4 pint). The water shall be kept reasonably cool (10*-15'C or 5Q.0-60.0#F) and shall be placed close to the workplace so that the worker can reach it without abandoning the work area. The workers should be encouraged to salt their food abundantly during the hot season and particu larly during hot spells, if the workers are unacclima tized, salted drinking water shall be made available in a concentration of 0.1% (1g NaCl to 1,0 liter or 1 level tablespoon of salt to 15 quarts of water). The added salt shall be completely dissolved before the water is distributed, and the water shall be kept reasonably cool. V. Other Considerations A. Clothing; The permissible heat exposure TLVs are valid for light summer clothing as customarily worn by workers when working under hot environmental conditions. If special cothing is required for perform ing a particular job and this clothing is heavier or it impedes sweat evaporation or has higher insulation value, the worker's heat tolerance is reduced, and the permissible heat exposure limits indicated in Table 1 and Figure 1 are not applicable. For each job catego ry where special clothing is required, the permissible heat exposure limit shall be established by an expert. S. Acclimatization and Fiwess: Acclimatization to heat involves a series of physiological and psycholog ical adjustments that occur in an individual during his first week of exposure to hot environmental condi tions. The recommended heat stress TLVs are valid for acclimated workers who are physically fit, Extra caution must be employed when unacclimated or physically un-fit workers must be exposed to heat stress conditions, Rvfanncai: 1. Health Factors Involved m Working Under Conditions o'! Heat Stress. WHO Technical Report Series No. 412 (1969). 74 2. 0ukai-0o6s. F N. end A. Heweftel: Development ot Permissible Heat Exposure Limits lor Occupational Wont. ASHRAE Journal 15(9).57-62 (Sept. 1973). 3. Mlnerd, 0.: Prevention ol Heal Casualties m Marine Corps Recruits. Period ol 1955-50. with Comparative Incidence Rates and Climatic Heat Stresses <n Other Trailing Categories. Research Report No 4. Contract No MR 005 01-0001.01. Naval Mebical Research Institue. Bethesda. M0 (Feb. 21, 1961). Published in Military Medicine 125(44): 251-272 (April 1961). 4. Mlnard, 0. and A. L. 0'BrlM: Pear Casualties in the Navy and Marine Corps 1959-1952 with Appendices on Bit field Use of the Wet Bulb-Globe Temperature Index. Research Report No. 7. Contract No. MR 005.01-0001.01, Naval Medical Research Institute, Bettiesda. MD (March 12. 1964). 5. Aitrand, Per-0lof and Kiara Rodahl: Textbook ot Work Physiology McGraw-Hill Book Co.. New York. San Francisco (1970). B. Ergonomics Guide to Assessment of Metabolic and Cardiac Costs of Physical Work. Am. Ind. Hyg. Assoc. J. 32:560 (1971). 7. Energy Requirements lor Physical Work. Research Progress Report No. 30. Purdue Farm Cardiac Project. Agricultural experiment Sta- - bon, West Lafayette. IN (1961). B. Dirmlrt, i. V. G. A. and R. Piamora: Energy. Wont and Leisure. Hememann Educational Books. Ltd.. London (1967). 9. likmaM. G. E., A. Muller and H. Spltzar Der Kalorienixdarf bte Gewerblicfier Arbeit. ArbiitsotiysiQt. 74:156 (1950). IONIZING RADIATION The Committee accepts the philosophy and recom mendations of the National Council on Radiation Pro tection and Measurements (NCRP) for the ionizing ra diation TLV. The NCRP is charted by Congress to, in part, collect, analyze, develop and disseminate infor mation and recommendations about protection against radiation and about radiation measurements, quantities and units, including development of basic concepts in these areas. NCRP Report No. 39 pro vides basic philosophy and concepts leading to pro tection criteria established in the same report.'" Other NCRP reports address specific areas ot radiation pro tection and, collectively, provide an excellent basis for establishing a sound program for radiation con trol. The Committee recommends the listed refer ences as substantative documentation of a sound basis for ionizing radiation protection. The committee also strongly recommends that all exposures to ioniz ing radiations be kept as low as reasonably achiev able within the stated guidance. Haftrenc**.- 1. Basic Radation Protection Criteria. NCRP Report No. 39 (January 15, 1971). 75 AP00055763 2. Mammum Pemvsnoie Body Burdens and Mattrmjm Permissible Con centrations o/ Rao'ionvcooes m Air and m Water hr Occupational Ex posure National ESureau of Standards Handbook 69. [June S. 1959). i (August 19631 Avails')le as NCflP Rtoort No. 22 The above documents, as well as information on nu merous other NCPP Reports addressing specific subtects in ionizing radiation protection ate available from: NCRP Publications. PO Box 30175. Washing ton. DC 20014. LASERS The threshold limit values are for exposure to laser radiation under conditions to which nearly all workers may be exposed without adverse effects. The values should be used as guides in the control of exposures and should not be regarded as fine lines between safe and dangerous levels. They are based on the best available information from experimental studies. Limiting Apertures The TLVs expressed as radiant exposure or irradiance in this section may be averaged over an aper ture of 1 mm except for TLVs for the eye in the spec tral range of 400-1400 nm, which should be averaged over a 7 mm limiting aperture (pupil); and except for all TLVs for wavelengths between 0.1-1 mm where the limiting aperture is 10 mm. No modification of the TLVs is permitted for pupii sizes less than 7 mm. The TLVs far "extended sources" apply to sources which subtend an angle greater than a (Table 7) which varies with exposure time. This angle is not the beam divergence of the source. Correction Factors A and 8 (C, and CB) The TLVs for ocular exposure in TaWes 4 and 5 are to be used as given for all wavelength ranges. The TLVs for wavelengths between 700 nm and 1049 nm are to be increased by a uniformly extrapolated factor (Ca) as shown in Figure 2. Between 1049 nm and 1400 nm, the TLV has been increased by a factor (Q<) of five. For certain exposure times at wavelengths be tween 550 nm and 700 nm, correction factor (Cfl) must be applied. The TLVs for skin exposure are given in Table 6. The TLVs are to be increased by a factor (C4) as shown in Figure 2 for wavelengths between 700 nm and 1400 nm. To aid in the determination of TLVs for exposure durations requiring calculations of fraction al powers Figures 3. 4, 5 and 6 may be used. 76 Repetitively Pulsed Lasers Sines there are few experimental data for multiple pulses, caution must be used in the evaluation ol such exposures. The protection standards for irradiance or radiant exposure in multiple pulse trams have the following limitations: (1) The exposure from any single pulse in the train is limited to the protection standard for a single com parable pulse. (2) The average irradiance for a group of pulses is limited to the protection standard as given in Tables 4. 5. or 7 of a single pulse of the same duration as the entire pulse group. (3) When the Instantaneous Pulse Repetition Frequency (PRF) of any pulses within a train exceeds one, the protection standard applicable to each pulse is reduced as shown in Figure 6 for pulse durations less than 10-4 second. For pulses of greater duration, the following formula should be followed: Standard ( s,n^ie Pulse\ - Standard (pulse hr) \ in train / n where: n = number of pulses in train r = duration of a single pulse in the train Standard (nr) = protection standard of one pulse having a duration equal to nr sec onds. : f j ; i ! | Figure 2 -- TLV correction factor for A = 700 - 1400 nm* 'ForA = 700 - 1049 nm. 0, = lO'TM-TM' For \ - 1050 - 1400 nm, C, = 5 77 AP00055764 Spectral Region uvc UVB TABLE 4 Threshold Limit Value for Direct Ocular Exposures (Intrabeam Viewing) from a Laser Beam Exposure Time. Wave Length _ _ (t) Seconds 200 nm to 2B0 nm 2B0 nm to 302 nm 303 nm 304 nm 305 nm 306 nm 307 nm 308 nm 309 nm 310 nm 311 nm 312 nm 313 nm 314 nm 10-* to 3 x 10< TLV 3 mJ cm'* 3 4 6 10 16 25 40 63 100 160 250 400 630 \ > / not to exceed 0.56 t1'* J cm ' fort S 10$. UVA Light IR-A IR-B & C 315 nm to 400 nm O .4 ** " 400 nm to 700 nm 400 nm to 700 nm 400 nm to 549 nm 550 nm to 700 nm 550 nm to 700 nm 400 nm to 700 nm 700 nm to 1049 nm 700 nm to 1049 nm 1050 nm to 1400 nm 1050 nm to 1400 nm 700 nm to 1400 nm 1.4 to 103/xm i. " <> 10'8 to 10 10 to 10s IQ3 to 3 x 10< 10-Mo 1.8 x 10'5 1.8 X 10- to 10 10 to 10* 10 to T, T, to 10* 10" to 3 x 10-* IQ Mo 1.8 x 10`5 1.8 x 10 5 tOl05 10-Mo ID'4 10'Mo 10a 10:` to 3 x 10* 10 Mo IQ'7 10 7 to 10 10 to 3 X 10* .56 \v* J cm 2 1.0 J cm 1 1.0 mW cm"2 5 x 10''J cm 2 1.8 (t/ VT) mJ cm 2 IDmJ cm * 1.8 (t/ VT-) mJ cm 2 lOCpinJ cm * C* fiVJ cm * 5 C.4 x 10 7 J cm 2 1.8 C i [U VT") mJ cm 4 5 x 10 " J cm 9(t/ VT") mJ cm 7 320 0., ,,W cm 2 10 J cm2 0.56 VT"J cm ' 0.1 W cm ` Ci See fig 2. CA - 1 lor A - 400 to 549 rim; C,, * .......... * lor * - 550 to 700 nm T, - 10 slot ^ - 400 to 549 nm. T, * 10 * 10....- " v'"`lor >. 5S0 ?o 700 n AP00055765 AP00055766 o03 l i i i i i i 00 TABLE 5 Threshold limit Values for Viewing a Difluse Reflection of a User Beam or an Extended Source User Spectral Reaion UV Light IR-A IR-B & C Wave Lenoth 200 nm to 400 nm 400 nm to 700 nm 400 nm to 549 nm 550 nm to 700 nm 550 nm to 700 nm 400 nm to 700 nm 700 nm to 1400 nm 700 nm to 1400 nm 700 nm to 1400 nm 1.4/xm lo 10*/xm Exposure Time, (t) Seconds 10-Mo 3 x 104 10-Mo 10 10 to 10-* 10 to T, T, to 104 10Mo3 x to* 10"* to 10 10 to TO3 10* to 3 X 104 10"* to 3 x 10' CC*. and 7, are the same as in lootnole to Table 4. TLV Same as Table 4 10 V t J cm-2 sr' 21 J cm"* sr'1 3.83 (t/ Vl~)J cm-* sr1 21 CB J cm"*sr`' 2.1 0flt x io-"W cm"2* sr'1 10 C< VT J cm'1 sr" * 3.83 C,, (1/ ITT) J cur* sr 1 0.64 C* W cm-2 * sr'1 Same as Table 4 TABLE 6 Threshold Limit Value for Skin Exposure from a Laser Beam Spectral Region UV Ught & IR-A IR-A IR-B & C Wave Length 200 nm to 400 nm 400 nm to 1400 nm 1.4 jum lo 10* ftm Exposure Time, ft) Seconds 10-Mo 3 x 104 10-Mo 10"' 10'Mo 10 10 to 3 x 10< 10-Mo 3 x 104 C, = 1.0 tor * - 400-700 nm; see Figure 2 for A - 700 to 1400 nm. TW_____________________ Same as Table 4 2 C,, x 10-a J cm * 1.1 CA VT~J cm'* 0.2 C.< W cm-* Same as Table 4 T L V IRRADIANCC (W cm Figure 3a -- TLV for intrabsam (direct) viewing of laser beam (400-700 nm). Figure 4a -- TLV for laser exposure of skin and eyes for far-in frared radiation (wave-lengths greater than t.4 am). Figure 3b -- TIV for intrabeam (direct) viewing of CW laser beam (400-1400 nm) 82 Figure 4b -- TLV for CW laser exposure of skin and eyes for far-infrared radiation (wave-lengths greater than 1.4 ^m). 83 AP00055767 H v * T 6 S *TE 0 **G J>CC l J cm" Figure 5a -- TLV for extended sources or diffuse reflections of laser radiation (400-700 nm). Figure 5b -- TLV for extended sources or diffuse reflections of laser radiation (400-1400 nm), 84 Figure 6 -- Muttiplieatve correction factor for repetitively pulsed lasers having pulse durations less than 10"* second. TLV for a single pulse of the pulse train Is multiplied by the above correction factor. Correction factor for PHF greater fian 1000 Hz is 0.06. TABLE 7 Limiting Angle to Extended Source Which May Be Used for Applying Extended Source TLVs Exposure Duratlonls) 10"? 10"' 10"T 10"* 10"s 10"< to-3 Angle a imratf) 8.0 5.4 3.7 2.5 1.7 2.2 3.6 Exposure Durations) io-3 10-1 1.0 10 10* 10s 10* Angle a (mrad) 5.7 9.2 15 24 24 24 24 85 AP00055768 NOISE These threshold limit values refer to sound pres sure levels and durations of exposure that represent conditions under which it is believed that nearly all workers may he repeatedly exposed without adverse effect on their ability to hear and understand normal speech. Prior to 1979. the medical profession had de fined hearing impairment as an average hearing threshold level in excess of 25 decibels (ANSI-S3.61969) at 500, 1000. and 2000 Hz, and the limits which are given have been established to prevent a hearing loss in excess of this level.**1 The values should be used as guides in the control of noise exposure and, due to individual susceptibility, should not be regard ed as fine fines between safe and dangerous levels. It should be recognized that the application of the TLV for noise will not protect all workers from the ad verse effects of noise exposure. A hearing conserva tion program with audiometric testing is necessary when workers are exposed to noise at or above the TLV levels. Continuous or Intermittent The sound level shall be determined by a sound level meter, conforming as a minimum to the require ments of the American National Standard Specifica tion for Sound Level Meters. Si .4 (1971) Type S2A, and set to use the A-weighted network with slow meter response. Duration of exposure shall not ex ceed (hat shown in Table 8. These values apply to total duration of exposure per working day regardless of whether this is one continuous exposure or a number of short-term expo sures and does include the impact and impulsive type of noise that contributes to the sound level meter reading at slow response. When the daily noise exposure is composed of two or more periods of noise exposure of different levels, their combined effect should be considered, rather than the individual effect of each. If the sum of the following fractions: Ti ' T* ` ` ' T,, exceeds unity, then, the mixed exposure should be considered to exceed the threshold limit value. Ci in- *ln 1979. the American Academy of Ophtialmoiogy and Otolargyngology (AAOO) included 3000 Hz in their hearing Impairmentformula. 86 Table 8 Threshold Limit Values Duration per Day Hours 16 8 4 2 1 1/2 1/4 1/8 Sound Level dBAt 80 85 90 95 100 105 110 115' tSound level in decibels are measured on sound level meter, conform ing a$ a minimum to the requirements of the American National Stan dard Specification for Sound Level Meters. S1.4(t97J) Type S2A. and set to use the A-wcjghted network with slow meter response. 'No exposure to continuous or intermittent in excess of I IS <J8A dicates the total duration of exposure at a specific noise level, and Ti indicates the total duration of ex posure permitted at that level. All on-the-job noise ex posures of 80 dBA or greater shall be used in the above calculations. IMPULSIVE OR IMPACT NOISE It is recommended that exposure to impulsive or impact noise shall not exceed the limits listed in Table 9 or taken from Figure 7. No exposures in ex cess of 140 decibels peak sound pressure level are permitted. Impulsive or impact noise is considered to be those variations in noise levels that involve max ima at intervals of greater than one per second. Where the intervals are less than one second, it should be considered continuous. Table 9 Threshold Limit Values Impulsive or Impact Noise Sound Level dB" 140 130 120 Permitted Number of Impulses or Imoacts perdav 100 1000 10.000 "Decibels peak sound pressure level, re 20 Pa 87 D fC IH LS riA K iO U KO A tiU U lf IC V Il Figure I -- Threshold Limit Values (TLV) for Radiofrequency/Microwave Radiation in Workplace (Whole Body SAR Less Than 0,4 W/kg). Figure 7 -- Threshold Limit Values for Impulse/Impact Noise. RADIOFREQUENCY/MICROWAVE RAOIATION These Threshold Limit Values (TLVs) refer to ra diofrequency (RF) and microwave radiation in the fre quency range `rom 10 kH2 to 300 6Hz, and represent conditions uncer which it is believed workers may be repeatedly exposed without adverse health effects. The TLVs shown in Table 10 are selected to limit the average whole body specific absorption rate (SAR) to 0.4 W/kg in any six minutes (0.1 hr> period for 3 MHz to 300 GHz, see Figure 8. Between 10 kHz and 3 MHz the average whole body SAR is stil! limited to 0.4 W/kg, but the plateau at 100 mW/cmz was set to pro tect against shock and bum hazards. Since it is usually impractical to measure the SAR, the TLVs are expressed in units that are measurable, viz. squares of the electric and magnetic field strengths, averaged over any 0,1 hour period. This 88 (cUrt/MUJ) *lisu9Q jaMo<j sOcjsav 89 AP00055770 "2 ai <o CO o X r- X J=: o3s iz: .<? It s x Xo *-OOoS rh** r- r^. fps^^-. f*-* CO CO CO co co Threshold Lim it Values oo oo 0 4u> oQJ* Tr3o CC Q 222 isssa O <> O S3 f- 90 can be expressed in units of equivalent plane wave power density for convenience. The electric field strength (E) squared, magnetic field strength (H) squared, and power density (PD) values are shown m Table 10. For near field exposures PD cannot be mea sured directly, dot equivalent plane wave power den sity can be calculated from the field strength mea surement data as follows: p PO in mW/cm2 = 377Q where: E2 is in volts squared (V2) per meter squared (nf>. where: PD in mW/cm2 - 37.7 H2 H2 is in amperes squared (A2) per meter squared (m2). These values should be used as guides in the eval uation and control of exposure to radiofrequency/mi crowave radiation, and should not be regarded as a fine line between safe and dangerous levels. Notes: 1. All Radiofrequency Radiation (RFR) exposures should be kept as low as reasonably possible given the current state of knowledge on human effects, particularly non-thermal effects. 2. For fields consisting of a number of frequencies, the fraction of the protection guide incurred within each frequency level should be determined and the sum of all fractions should not exceed unity. 3. For pulsed and continuous wave fields, the power density is averaged over the six minute period. 4. For partial body exposures at frequencies between 10 kHz and 1.0 GHz. the protection guides in Table 10 may be exceeded if the output power of a ra diating device is 7 watts or less. For example, if a hand held transmitter operating at 27 MHz has a maximum output of 5 watts, it would be excluded from any further field measurements. 5. The TLVs in Table 10 may be exceeded if the expo sure conditions ran be demonstrated to produce a SAR of less than 0.4 W/kg as averaged over the whole body and spatial peak SAR values less than 8.0 W/kg as averaged over any 1.0 gram of tissue. 91 AP00055771 For example., for frequencies from 3 to 30 MHz, the equivalent power density can be increased by a factor of 10 up to a limit of 100 mW/cm2. if it can be assured that exposed individuals are not in con tact with the ground plate. 6. At frequencies below 30 MHz. ungrounded objects such as vehicles, fences, etc., can strongly couple to RF fields. For field strengths near the TLV, shock and bum hazards can exist. Care should be taken to eliminate ungrounded objects, to ground such objects, or use insulated gloves when un grounded objects must be handled. 7. No measurement should be made within 5 cm of any object. 8. All exposures should be limited to a maximum (peak) electric field intensity of 100 kV/m. ULTRAVIOLET RADIATION* These threshold limit values refer to ultraviolet ra diation in the spectral region between 200 and 400 nm and represent conditions under which it is be lieved that nearly all workers may be repeatedly ex posed without adverse effect. These values for expo sure of the eye or the skin apply to ultraviolet radiation from arcs, gas, and vapor discharges, fluo rescent, and incandescent sources, and solar radia tion, but do not apply to ultraviolet lasers.' These val ues do not apply to ultraviolet radiation exposure of photosensitive Individuals or of Individuals concomi tantly exposed to photosensitizing agents.'" These values should be used as guides in the control of ex posure to continuous sources where the exposure duration shall not be less than 0.1 sec. These values should be used as guides in the con trol of exposure to ultraviolet sources and should not be regarded as a line line between safe and danger ous levels. Recommended Values: The threshold limit value for occupational expo sure to ultraviolet radiation incident upon skin or eye where irradiance values are known and exposure time is controlled am as follows: 1. For the near ultraviolet spectral region (320 to 400 nm) total irnidiance Incident upon the unprotected See Lasar TLVs. 92 skin or eye should not exceed 1 mW/cm? for periods greater than 103 seconds (approximately 16 minutes) and for exposure times less than 103 seconds should not exceed one J/cm2. 2. For the actinic ultraviolet spectral region (200 -- 315 nm), radiant exposure incident upon the un protected skin or eye should not exceed the values given in Table 11 within an 8-hour period. 3. To determine the effective irradiance of a broad band source weighted against the peak of the spectral effectiveness curve (270 nm). the follow ing weighting formula should be used: ^ E* S* AX where: Ef!T = effective irradiance relative to a monochromat ic source at 270 nm in W/cmz (J/s/cmz) = spectral irradiance in W/cmz/nm = relative spectral effectiveness (unitless) Ax = band width in nanometers Figure 9 -- Threshold Limit Values for Ultraviolet Radiation 93 AP00055772 TABLE 11 Relative Spectral Effectiveness by Wavelength* Wavelength (nm) 200 210 220 230 240 250 254 260 270 280 290 300 305 310 315 TLV (mJ/cm2) 100 40 25 16 10 7.0 6.0 4.6 3.0 3.4 4.7 10 50 200 1000 Relative Spectral Effectiveness s,, 0.03 0.075 0.12 0.19 0.30 0.43 0.5 0.65 1.0 0.88 0.64 0.30 0.06 0.015 0.003 `See Laser TLVs. TABLE 12 Permissible Ultraviolet Exposures Duration of Exposure Per Day Effective Irradiance, Et/r(^W/cm2) 8 firs................................................................... 0,1 4 hrs................................................................... 2 hrs................................................................... 0.2 0.4 1 hr..................................................................... 0.8 30 min............................................................... 15min............................................................... 1.7 3.3 10 min................................................................ 5 5 min......................................... 10 1 min.................................................................. 50 30 sec................................................................. 100 10 sec................................................................ 300 1 sec................................................................... 3,000 0.5 sec...................................... 6,000 0.1 sec........................................ 30,000 94 4. Permissible exposure time in seconds for expo sure to actinic ultraviolet radiation incident upon the unprotected skin or eye may be computed by dividing 0.003 J/cm* by in W/cm2. The expo sure time may also be determined using Table 12 which provides exposure times corresponding to effective irradiances in^W/cm2. 5. All the preceding TLVs for ultraviolet energy apply to sources which subtend an angle less than 80. Sources which subtend a greater angle need to be measured only over an angle of 80. Conditioned (tanned) individuals can tolerate skin exposure in excess of the TLV without erythemal ef fects. However, such conditioning may not protect persons against skin cancer. Reference: 1. Sunlight and Man. Fi&patrick el at. Eds. Univ. 9f Tokyo Press. Tokyo. Japan (I974|. NOTICE OP INTENDED CHANGES (for 1984-85) These physical agents, with their corresponding values, comprise those for which either a limit has been proposed for the first time, or for which a change in the `Adopted" listing has been proposed. In both cases, the proposed limits should be consid ered trial limits that will remain in the listing for a period of at least one year, If after one year no evi dence comes to light that questions the appropriate ness of the values herein the values will be reconsi dered for the "Adopted" list. NOTICE OF INTENT TO ESTABLISH THRESHOLD LIMIT VALUES LASERS It is proposed that the following footnote be added to Table 6 {Threshold Limit Value for Skin Exposure from a Laser Beam). The IR-B and IR-C exposures to skin surface areas A(cm2) exceeding 1000 cm2, the TLV is (100,000/A) (mW/cm2); for areas greater than 10,000 cm2, the TLV is 10 mW/cm2. LIGHT AND NEAR-INFRARED RADIATION These Threshold Limit Values refer to visible and near-infrared radiation in the wavelength range of 400 95 AP00055773 nm to 1400 nm and represent conditions under which it is believed that nearly all workers may be exposed without adverse effect. These values should be used as guides in the control of exposure to light and should not be regardec as a fine line between safe and dangerous levels. Recommended Values: The Threshold Limit Value for occupational expo sure to broad-band light and near-infrared radiation for the eye apply to exposure in any eight-hour work day and require knowledge of the spectral radiance (Lx) and total irradiance (E) of the source as mea- TABIE 13 Spectral Weighting Functions for Assessing Retinal Hazards from Broad-Band Optical Sources Wavelength (nm) 400 405 410 415 420 425 430 435 440 445 450 455 460 465 470 475 480 485 490 495 500-600 600-700 700-1049 1050-1400 Blue-Light Hazard Function Ba 0.10 0.20 0.40 0.80 0.90 0.95 0.98 1.0 1.0 0.97 0.94 0.90 0.80 0.70 0.62 0.55 0.45 0.40 0.22 0.16 0.001 0.001 0.001 Burn Hazard Function Ra 1.0 2.0 4.0 8.0 9.0 9.5 9.8 10.0 10.0 9.7 9.4 9.0 8.0 7.0 6.2 5.5 4.5 4.0 2.2 1.6 1.0 1.0 |0|i7oo-x>/jasj 0.2 96 surod at the posttion(s) of the eye of the worKer. Such detailed spectral data of a white light source is gener ally only required if the luminance of the source ex ceeds 1 cd cm-?. At luminances less than this value theTLV would not be exceeded. The TIV's are: T. To protect against retinal thermal injury, the spec tral radiance of the lamp weighted against the function R (Table 13) should not exceed; 1400 2LAR*AA^1/at 400 (1)* where L* is in W cm-* sr1 nm-1 and t is the view ing duration (or pulse duration it the lamp is pulsed) limited to 1 to 10 s, and a is the angular subtense of the source in radians. If the lamp is oblong, a refers to the longest dimension that can be viewed. For instance, at a viewing distance r - 100 cm from a tubular lamp of length I = 50 cm, the viewing angle is; a = t/r = 50/100 = 0.5 rad (2) 2. To protect against retinal photochemical injury from chronic blue-light exposure the integrated spectral radiance of a light source weighted against the blue-light hazard function Bx (Table 13) should not exceed: 1400 ^ Ut8KAA ^ TOO Jem*2 sc' {ts 104s) (3a) (400 L Ba Aa ^ 10-2 Wcirr2 sr' (t > 104s) (3b) The weighted product of L* and B^ is termed L(blue). For a source radiance L weighted against the blue-light hazard function [L(blue)J which ex ceeds 10 mWcnr2*sr' in the blue spectral re gion. the permissible exposure duration Lw* in seconds is simply; W = TOO J cm-2 srVL (blue) (4) The latter limits are greater then the maximum permissibte exposure limits for 440 nm laser radiation (see Laser TLV) because a 2-3 mm pupil is as sumed rather than a 7 mm pupil for the Laser TLV. Fora light source subtending an anglea less than 11 mrd (0.011 radian) the above limits are relaxed such that the spectral irradiance weighted against the blue-light hazard function Bx should not ex ceed E(Qlue). 97 AP00055774 1400 ^ Ex# t# s 10 mJ# cm-1 (t^ 10* s) (5a} 1400 ^E,,* Bk Ax VW* cm3 (tfi 10* s) (5b) For a source where the blue light weighted irradiance E (blue) exceeds 1 fiW cm'1 is the maxi mum permissible exposure duration t,,0-r in sec onds is: Wr = tO mj cm"1 E (blue) (6) 3. Infrared Radiation: To avoid possible delayed ef fects upon the lens of the eye (cataractogenesis), the infrared radiation {A. > 770 nm) should be lim ited to 10 mWcrrr*. For an infrared heat lamp or any near-infrared source where a strong visual stimulus i;s absent, the near infrared (770-1400 nm) radiance as viewed by the eye should be limited to: 1400 ^L. AMS 0.6/a (7)' (or extended duration viewing conditions. This limit is based upon a 7 mm pupil diameter. AIRBORNE UPPER SONIC AND ULTRASONIC ACOUSTIC RADIATION These threshold limit values refer to sound pres sure levels that represent conditions under which it is believed that nearly all workers may be repeatedly ex posed without adverse effect. The values listed in Table 14 should be used as guides in the control of noise exposure and, due to individual susceptibility, should not b> regarded as fine lines between safe and dangerous levels. The levels for the third octave bands centered below 20 kHz are below those which cause subjective effects. Those levels for 1/3 octaves above 20 kHz are for prevention of possible hearing losses from subharmonics of these frequencies. 'Formulae (1) and (7) are empirical and are not. strictly spealdno, di mensionally correct. To make die formulae dimensionally correct, one would have to insert a dimensional correction factor k In the right hand numerator in each formula. For formula (1) this would be k, - 1 W rad* sh/fem2 $r). and for formula (7) k - 1 W* rad/{cm**sr). 96 TABLE 14 Permissible Ultrasound Exposure Levels Mid-Frequency ol Third-Octave Sand kHz 10 12.5 16 20 25 31.5 40 50 One-Third Octave -- Band Level in dB re 20 uPa 80 80 80 105 110 115 115 115 COLD STRESS These Threshold Limit Values (TLVs) are intended to protect workers from the severest effects of cold stress (hypothermia) and cold injury and to describe exposures to cold working conditions under which it is believed that nearly all workers can be repeatedly exposed without adverse health effects. The TLV ob jective is to prevent the deep body core temperature from falling below and to prevent cold injury to body extremities. Deep body temperature is the core temperature of the body as determined by rectal tem perature measurements. For a single, occasional ex posure to a cold environment a drop in core tempera ture of no lower than 35'C should be permitted. In addition to provisions for total body protection, the TLV objective is to protect all parts of the body with emphasis on hands, feet and head from cold injury. In(reduction to Cold Stress Fatal exposures to cold among workmen have al most always resulted from accidental exposures in volving failure to escape from low environmental air temperatures or from immersion in low temperature water. The single most important aspect of lifethreatening hypothermia is the fail in the deep core temperature of the body. The clinical presentations of victims of hypothermia are shown in Table 15 (taken from Dembert in AFP, January 1982). Workmen should be protected from expoure to cold so that the deep core temperature does not fall below 36C 99 AP00055775 TABLE 15 Progressive Clinical Preservations of Hypothermia* Core Temperature C F Clinical Signs 37.6 37 36 35 34 33 321 31/ 301 29/ 99.6 93.6 "Normal" rectal temperature "Normal" oral temperature 96.3 Metabolic rate increases in an attempt to compensate for heat loss 95.0 Maximum shivering 93.2 Victim conscious and responsive, with normal blood pressure 91.4 Severe hypothermia below this temper ature 89.6 T Consciousness clouded; blood pressure 87.8/ becomes difficult to obtain; pupils dilat ed but react to light shivering ceases 86.01 84.2/ Progressive loss of consciousness; muscular rigidity increases; pulse and blood pressure difficult to obtain; respi ratory rate decreases 28 82.4 Ventricular fibrillation possible with myocardial irritability 27 80.6 Voluntary motion ceases; pupils nonreactive to light; deep tendon and superficial reflexes absent 26 78.8 Victim seldom conscious 25 77.0 Ventricular fibrillation may occur spon taneously 24 22 \ 21/ 20 13 17 9 75.2 Pulmonary edema 71.61 Maximum risk of ventricular fibrilation 69.3/ 68.0 Cardiac standstill 64.4 Lowest accidental hypothermia victim to recover 62.6 Isoelectric electroencephalogram 48.2 Lowest artificially cooled hypothermia patient to recover ' Presentations approximately related to core temperature. Reprinted `ram the January 1932 issue of American Family Physician* published by the American Academy of Family Physicians. too (96.8'F); lower body temperatures will very likely re sult in reduced mental alertness, reduction in rational decision making or loss of consciousness with the threat of fatal consequences. Pain in the extremities may be the first early warn ing of danger to cold stress. During exposure to cold, maximum severe shivering develops when the body temperature has fallen to 35"C (95'F). This must be taken as a sign of danger to the workmen and expo sure to cold should be immediately terminated for any workman when severe shivering becomes evident. Useful physical or mental work is limited when severe shivering occurs. Since prolonged exposure to cold air. or to immer sion in cold water, at temperatures well above freez ing can lead to dangerous hypothermia, whole body protection must be provided. 1. Adequate insulating clothing to maintain core tem peratures above 36C must be provided to workers if work is performed in air temperatures below 4aC (40'F). Wind chiir or the coaling power of the air is a critical factor. The higher the wind speed and the lower the temperature in the work area, the greater the insulation value of the protective clothing re quired. An equivalent chill temperature chart relat ing the actual dry bulb air temperature and the wind velocity is presented in Table 16. The equiva lent chill temperature should be used when esti mating the combined cooling effect of wind and low air temperatures on exposed skin or when de termining clothing insulation requirements to maintain the deep body core temperature. 2. Unless there are unusua) or extenuating circum stances cold injury to other than hands, feet, and head is not likely to occur without the develop ment of the initial signs of hypothermia. Older workers or workers with circulatory problems re quire special precautionary protection against cold injury, The use of extra insulating clothing and/or a reduction in the duration of the exposure period are among the special precautions which should be considered. The precautionary actions to be taken will depend upon the physical condition of the worker and should be determined with the ad vice of a physician with knowledge of the cold * Wind ctiill factor is a unit of hat toss from a body defined in watts o meter sfluared per hour being a Function of the air temperature end wind velocity upon the exposed body. 101 AP00055776 s 102 stress factors and the medical condition of the worker. Evaluation and Control For exposed skin, continuous exposure should not be permitted when the air speed and temperature re sults in an equivalent chill temperature of -32C (~25*F). Superficial or deep local tissue freezing will Occur only at temperatures below -rc regardless of wind speed. At air temperatures of 2C (35.6'F) or less it is im perative that workers who become immersed in water or whose clothing becomes wet be immediately pro vided a change of clothing and be treated for hypo thermia. Recommended limits for properly clothed workers for periods of work at temperatures below freezing are shown in Table 17. Special protection of the hands is required to maintain manual dexterity for the prevention of acci dents: 1. If fine work is to be performed with bare hands for more than 10-20 minutes in an environment below 16C {60oF), special provisions should be estab lished for keeping the workers' hands warm. For this purpose, warm air jets, radiBnt heaters {fuel burner or electric radiator) or contact warm plates may be utilized. Metal handles of tools and control bars shall be covered by thermal insulating materi al at temperatures below -1"G (30'F) 2. If the air temperature falls below 1SC (60F) for sedentary. 4C (40F) for light, -7C (20F) for moderate work and fine manual dexterity is not re quired then gloves shall be used by the workers. To prevent contact frostbite, the workers should wear anti-contact gloves. 1. When cold surfaces below -7C (20F) are within reach, a warning should be given to each worker by his supervisor to prevent inadvertent contact by bare ekin. 2. if the air temperature is -17.5QC (0F) or lass, the hands should be protected by mittens. Machine controls and toots for use in cold conditions should be designed so that they can be handled without removing the mittens. Provisions for additional total body protection is required if work is performed in an environment at or below 48C (40F). The workers shall wear cold protec- 103 AP00055777 TABLE 17 Work/Warm-up Schedule for Four-Hour Shift* Air Temperature -- Sunny Sky No Noticeable Wind 5 mph Wind 10 mph Wind 15 mph Wind 20 mph Wind -BC (approx.) -F Max. Wnrt Period No. of Breaks Max. uwy Period W4 Breaks Max. Work Period No. of Breaks Max. Work Period Nu. in Breaks Max. Work Period No ol Breaks 1. -26'Cto -28* C -15F to -19UF (Norm, b eaks) 1 (Norm, b nks) l 75 mins. 2 55 mins. 3 40 miits. 4 2. -2rcto -31 C -20F to -24F (Norm, b eaks) 1 75 mins. 2 55 mins. 3 44 mins. 4 30 mins. 5 3. -32Cto -34a C -25*F to -29F 4. -35cto -src -30F to -34aF 5. -38*Cto -39 Q -35F to -39F S. -40Cto -42C -40F to -44F 7. -43"C & below -45F & below 75 mins. 2 55 mins. 3 40 mins. 4 30 mins. 5 Non-emergency work should cease 55 mins. 3 40 mins. 4 40 mins. 4 30 mins. 5 30 mins. 5 Non-emergency work should cease Non-emergency work should cease 1 30 mins. 5 Nan-emergency work should cease Ncn-emer oency work should cease Notes for Table 17: 1. Schedule applies to moderate to heavy work activity with warm-up breaks of ten (10) minutes in a warm location. For Light-to-Moderate Work (limited physical movement): apply the schedule one step lower. For example, al -30F with no noticeable wind (Step 4), a worker at a job with little physical movement should have a maximum work period of 40 minutes with 4 breaks In a 4-hour period (Step 5). 2. The following is suggested as a guide for estimating wind velocity. If accurate information is not available: 5 mph: light flag moves; 10 mph: light (lag fully extended; 15 mph: raises newspaper sheet; 20 mph: blowing and drifting snow, 3. If only the Wind Chill Factor Is available, a rough rule of thumb for applying it rather than the temperature and wind velocity factors given above would be: 1) special warm-up breaks should be initiated at a wind chill of about 1750 W/m2/hr; 2) All non-emergency work should have ceased al or before a wind chill of 2250 W/m2/hr. In general the warm-up schedule provided above slightly under-compensates for the wind at the warmer temperatures, assuming acclimatization and clothing appropriate for winter work. On the other hand, the chart slightly over-compensates (or the absolute temperatures in the colder ranges, since windy conditions rarely prevail at extremely low temperatures. from Occupational Health & Safety Division, Saskatchewan Dept of Labour. AP00055778 live clothing appropriate for the level of cold and physical activity: 1. If the air velocity at the job site is increased by wind, draft, or artificial ventilating equipment, the cooling effect of the wind shall be reduced by shielding the work area, or by wearing an easily removable outer windbreak layer garment. Wind chill cooling rates are illustrated in Figure 10 and Table 13. 2. If only light work is involved and if the clothing on the worker may become wet on the job site, the outer layer of the clothing in use may be of a type impermeable to water. With more severe work under such conditions the outer layer should be water repellent, and the outerwear should be changed as it becomes wetted. The outer gar ments must include provisions for easy ventilation in order to prevent wetting of inner layers by sweat. If work is done at normal temperatures or in a hot environment before entering the cold area, the employee shall make sure that his clothing is not wet as a consequence of sweating. If his cloth ing is wet, the employee shall change into dry clothes before entering the cold area. The workers shall change socks and any removable felt insoles at regular daily intervals or use vapor barrier boots. The optimal frequency of change shall be determined empirically and will vary individually and according to the type of shoe worn and how much the individual's feet sweat. 3. If extremities, ears, toes and nose, cannot be pro tected sufficiently to prevent sensation of exces sive cold or frostbite by handware, footwear and face masks, these protective items shall be sup plied in auxiliary heated versions. 4. If the available clothing does not give adequate protection to prevent hypothermia or frostbite, work shall be modified or suspended until ade quate clothing is made available or until weather conditions improve. 5. Workers handling evaporative liquid (gasoline, al cohol or cleaning fluids) at air temperatures below 40"F shall take special precautions to avoid soak ing of clothing or gloves with the liquids because of the added danger of cold injury due to evapora tive cooling. Special note should be taken of the particularly acute effects of splashes of "cryogenic fluids'' or those liquids with a boiling point only just above ambient temperatures. 106 Rpura 10 -- Wind chill cooling rates. Adapted from Canadian Department o t the Environment, Atmospheric Environment Service i BOOH a 3d Sa3J.3WOH>l-033dS ONIM eiO CD T ofl- 1*5 OJ CD T cn 5 rri V) _l 2o n fcj O' 3 5 a: U1 a. s u) tce < in 107 AP00055779 TABLE 18 Wind Chill Cooling Rate Effects' Wind Chill Rates (Watts/m2/hr) Comments/Effects 7Q0 Conditions considered comfortable when dressed for skiing. 1200 1400 Conditions no longer pleasant for out door activities on overcast days. Conditions no longer pleasant for out door activities on sunny days. 1600 2300 Freezing of exposed skin begins for most peopfe depending on the degree of activity and the amount of sunshine. Conditions for outdoor travel such as walking become dangerous. Exposed areas of the face freeze in less than 1 minute for the average person. 2700 Exposed flesh will freeze within half a minute for the average person. 'Prom Canadian Department of the Environment, Atmosphere Environ ment Service. Work-Warming Regimen If work is performed continuously in the cold at an equivalent chill temperature (ECT) or below -7*C {20F) heated warming shelters {tents, cabins, rest rooms, etc.) shall be made available nearby and the workers should be encouraged to use these shelters at regular Intervals, the frequency depending on the severity of the environmental exposure. The onset of heavy shivering, frostnip, the feeling of excessive fa tigue. drowsiness, irritability, or euphoria, are indica tions for immediate return to the shelter. When enter ing the heated shelter the outerlayer of clothing shall be removed and the remainder of the clothing loosened to permit sweat evaporation or a change of dry work clothing provided, A change of dry work clothing shall be provided as necessary to prevent workers from returning to their work with wet cloth ing. Dehydration, or the loss of body fluids occurs in sidiously in the cold environment and may increase the susceptibility of the worker to cold injury due to a significant change in blood flow to the extremities. Warm sweet drinks and soups should be provided at 108 the work site to provide caloric intake and fluid vol ume. The intake of coffee should be limited because of a diuretic and circulatory effect. For work practices at or below -12aC (105F) ECT the following shall apply: 1. The worker shall be under constant protective ob servation (buddy system or supervision). 2. The work rate should not be so high as to cause heavy sweating that wilt result in wet clothing; if heavy work must be done, rest periods must be taken in heated shelters and opportunity for changing into dry clothing shall be provided. 3. New employees shall not be required to work full time in cold in the first days until they become ac customed to the working conditions and required protective clothing. 4. The weight and bulkiness of clothing shall be in cluded in estimating the required work perfor mance and weights to be lifted by the worker. 5. The work shall be arranged in such away that sit ting still or standing still for long periods is min imized. Unprotected metal chair seats shall not be used. The worker should be protected from drafts to the greatest extent possible. 6. The workers shall be instructed in safely and health procedures. The training program shall in clude as a minimum instruction in: a. Proper rewarming procedures and appropriate first aid treatment. b. Proper clothing practices. c. Proper eating and drinking habits. d. Recognition of impending frostbite. e. Recognition signs and symptoms of impending hypothermia or excessive cooling of the body even when shivering does not occur. f. Safe work practices. Special Workplace Recommendations Special design requirements for refrigerator rooms include the following: 1. In refrigerator rooms, the air velocity should be minimized as much as possible and should not ex ceed 1 meter/sec (200 fpm) at the job site. This can be achieved by properly designed air distribution systems. 109 AP00055780 2 Special wind protective clothing shall be provided based upon existing air velocities to which workers are exposed. Special caution shall be excercised when working with toxic substances and when workers are exposed to vibration. Cold exposure may require reduced ex posure limits. Eye protection for workers employed out-of-doors in a snow and/or ice-covered terrain shall be sup plied. Special safety goggles to protect against ultra violet light and glare (which can produce temporary conjuntivitis and/or temporary loss of vision) and blowing ice crystals are required when there is an ex panse of snow coverage causing a potential eye ex posure hazard. Workplace monitoring is'required as follows: 1. Suitable thermometry should be arranged at any workplace where the environmental temperature is below 16C {60F) to enable overall compliance with the requirements of the TLV to be mai ntained. 2. Whenever the air temperature at a workplace fails below -1C (30*F), the dry bulb temperature should be measured and recorded at least every 4 hours. 3. in indoor workplaces, the wind speed should also be recorded at least every 4 hours whenever the rate of air movement exceeds 2 meters per second (5 mph). 4 In outdoor work situations, the windspeed should be measured and recorded together with the air temperature whenever the air temperature is below -VC (30F). 5. The equivalent chill temperature shall be obtained from Table 16 in all cases where air movement measurements are required, and shall be recorded with the other data whenever the equivalent chid temperature is below -7C {20*F). Employees shall be excluded from work in cold at -tC (SCPF) or below if they are suffering from dis eases or taking medication which interferes with nor mal body temperature regulation or reduces toler ance to work in cold environments. Workers who are routinely exposed to temperatures below -24C (-10F) with wind speeds less than five miles per hour, or air temperatures below -18C (0F) with wind speeds above five miles per hour should be medically certified as suitable for such exposures. 110 Trauma sustained in freezing or subzero condi tions requires special attention because an iniured worker is predisposed to secondary cold injury. Spe cial provisions must be made to prevent hypothermia and secondary freezing of damaged tissues in addi tion to providing for first aid treatment. HAND-ARM (SEGMENTAL) VIBRATION These threshold limit values (Table 19) refer to component accelerations levels and durations of ex posure that represent conditions under which it is be lieved that most workers may be exposed repeatedly without progressing beyond Stage 3 of the Taylor-Pelmear Classification System for Vibration-induced White Finger (VWF, also known as Raynaud's Phe nomenon of Occupational Origin). Since there is a paucity of dose-response relationships for VWF, these recommendations have been derived from epidemio logical data from forestry, mining, and metalworking. These values should be used as guides in the control of hand-arm vibration exposure and because of indi vidual susceptibility, should not be regarded as defin ing a boundry between safe and dangerous levels. It should be recognized that the application of the TLV alone for hand-arm vibration will not protect all workers from the adverse effects of hand-arm vibra tion exposure. The use of: 1) antivibration tools, 2) antivibration gloves. 3) proper work practices which keep the worker's hands and remaining body warm and also minimize the vibration coupling between the worker and the vibration tool are necessary to min imize vibration exposure, and 4) a conscienciously appMed medical surveillance program are ALL neces sary to rid VWF from the workplace. Continuous, Intermittent, Impulsive, orImpact Hand-arm Vibration The measurement of vibration should be per formed in accordance with the procedures and instru mentation specified by the Second Draft International Standard ISO/DIS 5349 (19B4). Guide for the Mea surement and the Assessment of Human Exposure to Vibration Transmitted to the Hand, and summarized below: The acceleration of a vibration handle or work piece should be determined In three mutually orthog onal directions at a point close to where vibration enters the hand. The directions shall preferably be 111 AP00055781 those forming the ISO biodynamic coordinate system, but may be a closely related basicentric system with its origin at the interface between the hand and the vibrating surface (see Figure 11) to accommodate dif ferent handles or work piece configurations. A small and lightweight transducer shall be mounted so as to record accurately one or more orthogonal compo nents of the source vibration in the frequency range from 5 to 1500 Hz. Each component should be fre quency-weighted by a filter network with gain charac teristics specified by the ISO for human-response vi bration measuring instrumentation, to account for the change in vibration hazard with frequency (see Figure 12), Assessment of vibration exposure should be made for EACH applicable direction (X, Y,,, Zh) since vibra tion is a vector quantity (magnitude and direction). In each direction, the magnitude of the vibration during normal operation of the power tool, machine or work piece shall be expressed by the root-mean-square (rms) value of the frequency-weighted component ac celerations, in units of meters per second squared (m/'s2), or gravitational units (g), the largest of which, a*, forms the basis for exposure assessment. For each direction being measured, linear integra tion shall be employed for vibrations that are of ex tremely short duration or vary substantially in time, If the total daily' vibration exposure in a given direction is composed of several exposures at different rms ac celerations. then the equivalent, frequency-weighted component acceleration in that direction shall be de termined in accordance with the following equation; Figure 11 -- Siodynamic and basicentric coordinate systems for tne hand, showing the directions of the accel eration components (ISO 5349). where: T = 2 T,- t T = total daily exposure duration %x,~ith frequency-weighted, rms acceleration com ponent with duration T,. These computations may be performed by commer cially available human-response vibration measuring instruments. 112 1/3 OCTAVE-SAW CENTRE FREOUENCY (Mi) Figure 12 -- Gain characteristics of the filter network used to frequency-weight acceleration components (con tinuous line). The filter tolerances (dashed lines) are provisional, and are those contained in ISO 5349. 113 AP00055782 TABLE 19 Threshold Limit Values tor Exposure of the Hand to Vibration in Either X,,, Y~lh Directions Total Daily Exposure Duration' Values of the Dominant/ Frequency-Weighted, rms, Component Acceleration Which Shall not be exceeded*' 4 hours and less than 8 2 hours and less than 4 1 hour and less than 2 Less than 1 hour m/s2 4 6 8 12 g 0.40 0.61 0.81 1.22 'The total time vibration enters the hand per day- whether continuously or interrmnenily. rUsually one axis ol vibration is dominant over (he remaining two axis. If one or more vibration axis exceeds the Total Daily Exposure then the TLV nas been exceeded. "1 g - 9.81 m/s* Holes: Ttble 19: 1. Hardly any person exposed at or below the TLVs for vibration contained in Table 19 has progressed to Stage 3 Vibration White Finger, in the TaylorPelmear classification, i.e., the point at which ex tensive blanching of all fingers has occurred and there is definite interference at work, home, and restricted social activities/2-7) 2. Acute exposures to frequency-weighted, rms, com ponent accelerations in excess of the TLVs for in frequent periods of time (a.g.. 1 day per week, or several days over a two-week period) are not nec essarily more harmful/2-4) 3. Acute exposures to frequency-weighted, rms, com ponent accelerations of three times the magnitude of the TLVs are expected to result in the same health effects after between 5 and 6 years of exposure.!2"41 4. Preventive measures, including specialized preem ployment and annual medical examinations to identify persons susceptible to vibration, should be implemented iri situations in which workers are or will be exposed to hand-arm vibration.'1-7) 114 5. To moderate the adverse effects of vibration expo sure. workers should be advised to avoid continu ous vibration exposure by cessation of vibration exposure for approximately 10 minutes per contin uous vibration hour. 6. Good work practices should be used, and should include instructing workers to employ a minimum hand grip force consistent with safe operation of the power tool or process, keep their body and hands warm and dry, and avoid smoking/2-3' 7. A transducer and its device for attachment to the vibrating source suitable for measurement pur poses together should weigh less than 15 grams, and should possess a cross-axis sensitivity of less than 10%. 8. The measurement by many (mechanically under damped) piezoelectric accelerometers of repeti tive. large displacement, impulsive vibrations, such as those produced by percussive pneumatic tools, is subject to error. The insertion of a suitable, lowpass, mechanical filter between the accelerometer and Ihe source of vibration with a cut-off fre quency of 1500 Hz or greater (and cross-axis sensi tivity of less than 10%) can help eliminate incorrect readings/3-4) 9. The manufacturer and type number of all appara tus used to measure vibration should be reported, as well as the value of the dominant direction and frequency-weighted, rms. component acceleration. Rsftrancss: t. Pyvkko I.: Vibration Syndrome. A Review. Vibration and Wont. pp. (24. 0. Dortionen. Ed. Institute of Occupational Health, Helsinki (t97S). 2. Vibration Whits Finger in Industry, W. Taylor and P. L. Pelmear. EOS. Academic Press. London (1975). 3. NIOSH: Proceedings ol the International Occupational Hand-Arm Vi bration Conterence. 0. E. Wasserman and W. Taylor, 60s. 0HEW NIOSH Pub. No. 77-170 (1977). 4. Brammer, J. J.: Threshold Limit for Hand-Arm Vibration Exposure Throughout the Workday. Vibration Effects on the Hand and Arm in Industry, pp. 291-301. A. J. 8rammer and W. Taylor. Eds. John Wiley 4 Sons, New York (1982). 5. Wisarman. 0. E. and W. Taylor Environmental and Occupational Medicine, Chap. 58, Occupational Vibration, pp. 743-749. W. N. Rom, 6d. Unte. Brown and Co.. Boston (1982). 8. NIOSH: Current Intelligence Bulletin #38: Vibration Syndrome. DHHS (NIOSH) Pot). No. 83-110(1983). 7. NIOSH: Vibration Syndrome, NIOSh Videotape #T77 (27 minutes). Cincinnati, OH. 115 APOOOi 8. International Organization for Standardization: Guide tor tn* Mea surement anc1 tns Assessment of Human Exposure to Vibration Trans mitted to the Hand. Second Dis 5349 international Orgamzanort :or Stanoarcuzaima Geneva im pfess. 1383). 9. International Organization for standardization: Human-Response Vi bration Measuring Instrumentation. Second Draft Piooosai DP 8041 ISO/TC 103/SC 3 n 99. International Organization for Standardiza tion. Geneva (tmpuolislted. 1982). PHYSICAL AGENTS UNOER STUDY The Physical Agents Committee ot ACGIH has ex amined the current literature and has not found suffi cient information to propose a TLV. However, these agents will remain under study during the coming year to examine new evidence indicating the need and feasibility for establishing a proposed TLV. Com ments and suggestions, accompanied by substantive documentation are solicited and should be forwarded to the Executive Secretary. ACGIH. Documentation summarizing the current status of the biological ef fects literature is available on those agents preceded by an asterisk ('). 1. 'Extremely Low Frequency (ELF) Radiation. Spe cifically. that portion of the spectrum from 0 to 300 Hz. 2. Magnetic Fields. Both pulsed and`continuous. 3. Laser Radiation. Specifically laser exposures of loss than one (1) nanosecond. 4. Vibration. Whole-body. 5. Pressure Variations. 116 'V-nia nn"" wmorence ot Governmental Industrial. : u^iepists waft organized Jn'1938 by ft group of gov*. ^jMfin***** hygterii8ts whocdaaS^(ift.fndT* ~- -^funif for free exchangeoCWeas, S*f*ehcie ard^ Kv HheDftfiTWtJofl'6fStanda/ds and techniques in'lnduv*l h&aSH^tnftj3otvfcifaooft Hoot a*official Gowrn^ ?-Mir w n-Jiv'`*wofdevote<* A thaf5avawheht'-tft?^ administrate and technical aspects of wditar beetthjj^ K-^f-j'Pprfodttsacntioonn^- Ti nhee aassssoocciiaattiioonn hhaass ccoonnttrriibbuutteedd ssiuibbatsatnai niT**^^ &' Jtaihr to the etawlooroant and.Iimmpprroovveemmeennttocf.fooffficfilacCiaf-^;^^ ?-'fhdusiUlaf health asndcee' tso'^(dfjudsubstyfTy <andtf;rifaiibor. The'''*--'?^ ; .VentUatipn and Threshold ft*, ~ S-Uncijtvvii AP00055785 1040 SILICATES and OTHER PUSTS(m) Natural graphite (7782-42-S] Soapstone TaLc (containing asbestos fibers) Coal dust OCCUPATIONAL SAFETY 8. HEALTH REPORTER 2-5 mg/tn^ f Respirable dust 5 mg/tn3 , Total dust 3 mg/m3r Respirable dust 6 mg/m3, Total dust Use asbestos TLV. However, should not exceed 2 rag/m3 respirable dust. If > than 5% quartz, use respirable quart2 value. Journal MEETINGS SCHEDULED Jane 12-14 -- Governor's Safety and Health Conference, Louisville, Ky! (Doug Peek, Ky. Occupational Safety and Health Program, 127 Building, Frankfort, Ky. 40601; tel: (502) 564-6895). June 13 -- Behavioral Sciences in Accident Prevention, Burbank, Calif, (The Training Institute, 616 S. Westmoreland Ave., Los Angeles, Calif. 90005; tel: (213) 385-6461). June 13 -- Employee Right-to-Know Seminar, Toledo, Ohio (Regulatory Resources, Inc., 1946 N. 13th Street, Tole do, Ohio 43624; tel: (419) 255-0008). June 17-19 -- Toxicology Update '85, Baltimore. Md. (Johns Hopkins University School of Medicine, 720 Rutland Ave., Baltimore, Md. 21205; tel: (301) 955-6046). June 17-21 -- Particle Characterization in Technology, Iowa City, Iowa (J.K. Beddow, Center for Particulate Mate rial Processing Sciences, Univ. of Iowa, Iowa City, Iowa 52242; tel: (319) 353-3842). June 18 -- Forklift Safety Training, Burbank, Calif. (The Training Institute, 616 S. Westmoreland Ave., Los Angeles, Calif. 90005; tel: (213) 385-6461). June 18-19 -- Safety/Management, a Behavioral Ap proach, Chicago, 111. (National Hazards Control Institute, P.O. Box 667, Easton, Pa 18044-0667; tel: (215) 258-7045). June 19 -- Worker's Right-to-Know, St Paul, Minn. (Kath leen Anne, Midwest Center for Occupational Health and Safety, 640 Jackson St, St. Paul, Minn. 55101; tel: (612) 221-3992). Jane 20 -- Workers' Compensation 1985, Burbank, Calif. (The Training Institute, 618 S. Westmoreland Ave., Los Angeles, Calif. 90005; tel: (213) 385-6461). June 24-26 -- Meeting Your Responsibility for Worker Training and Right to Know, Los Angeles, Calif. (Institute of Safety and Systems Management, University of Southern California. Los Angeles, Calif. 90089-0021; tel: (213) 743-6523/6524). June 24 -- Right-to-Know and OSHA Hazard Communica tions Training for Trainers, Boston, Mass. (National Hazards Control Institute, P.O. Box 667, Easton, Pa. 18044-0667; tel: (215) 258-7045). June 27-28 -- Stress Management Seminar, Boston, Mass. (National Hazards Control Institute, P.O. Box 667, Easton. Pa. 18044-0667; tel: (215) 258-7045). Jnly 8-12 -- Occupational Respiratory Protection No. 134, New Orleans, La. (Darell A. Bevis, Darell Bevis Associ ates, Inc., Rt. 2, Box 311, Sterling, Va. 22170; tel: (703) 430-7100). July 15-18 -- Advanced Occupational Respiratory Protec tion, New Orleans, La. (Darell A. Bevis, Darell Bevis Associ ates, Inc., Rt. 2, Box 311, Sterling, Va. 22170; tel: (703) 430-7100). July 15-19 -- Occupational Respiratory Protection, Los Angeles, Calif. (Institute of Safety and Systems Manage ment, University of Southern California, Los Angeles, Calif. 90089-0021; tel: (213) 743-6523). July 16-18 -- Managing Safety: Techniques That Work for the Safety Pro, Mt. Pocono, Pa. (Du Pont Company, Profes sional Development Seminars, Barley Mill Plaza No. 19, Wilmington, Del. 19898; tel: (302) 992-3602). July 22 -- Right-to-Know and OSHA Hazard Communica tions Training for Trainers, Pittsburgh, Pa. (National Haz ards Control Institute, P.O. Box 667, Easton, Pa. 18044-0667; tel: (215) 258-7045). July 22-26 -- Sampling and Evaluating Airborne Asbestos Dust, Los Angeles, Calif. (Institute of Safety and Systems Management, University of Southern California, Los Ange les. Calif. 90089-0021; tel (213) 743-6523). July 23-25 -- National Fire Research Strategy Confer ence, Gaithersburg, Md. (National Bureau of Standards, Attn.: Bud Levin, A263 Polymers Bldg., Gaithersburg, Md. 20899: tel.: (301) 921-2721). 5-30-85 Copyright 1985 by Tha Bureau of National Affairs. Inc. 009S-3237/S5/SO+.$0 AP00055786 CURRENT REPORT 1039 Coal dust FOOTNOTE: from: TO: 2 mg/m3 (respirable dust fraction < 5% quartz). 2 mg/m3 respirable dust fraction^111) m) For silicates and other dusts, the values are for dust containing less than 1% quartz in the total dust. For coal dust, the value is for coal dust containing less than 5% quartz in the respirable fraction. For materials containing more than these percentages of quartz, the environment should be evaluated against the TLV of 0.1 mg/m3 for respirable quartz. Even where the respirable quartz concentration is less than 0.1 rag/m3, the level of the major component should not exceed its TLV. SUBSTANCE________________________________________________________ Ethylene glycol dinitrate [628-96-6]Skin pp 0 .05 TWA mq/m3 0.3 STEL .... PP mq/m3 -- Formaldehyde [50-00-0] Lead arsenate [10102-48-4], as Pbj(A3O4)2 p-Nitrochlorobenzene [100-00-5] Nitroglycerin [55-63-0] - Skin 1,A2 -- 0 .5 0.05 1.5,A2 0.15 0.3 0.5 2, A2 -- -- -- 3, A2 -- -- -- Phenylhydrazine [100-63-0] Propylene glycol dinitrate [6423-43-4] Skin 5,A2 0.05 20,A2 0.3 10,A2 45, A2 __ SUBSTANCE SILICA, Si02 Crystalline Silica, fused [60676-86-0] Tripoli [1317-95-9] Amorphous Precipitated silica Silica gel DUSTS TLV Use quarts value. 0.1 mg/m3 of contained quartz, respirable dust 5 mg/m3 Respirable dust 10 mg/nj2. Total dust 5 rag/m3. Respirable dust 10 mg/m3/ Total dust 5-30-65 Occupational Safety & Health Reporter AP00055787 1038 OCCUPATIONAL SAFETY 4 HEALTH REPORTER STEL VALUES DELETED FROM THE FOLLOWING CHEMICAL SUBSTANCES: n-Amyl acetate sec-Amyl acetate Asphalt (petroleum) fumes Benzene Biphenyl 2-Butoxyethanol sec-Butyl acetate tert-Butyl acetate Crotonaldehyde Cumene Cyclohexane Cyclohexanone Cyc1opentadiene Cyclopentane Dibutyl phthalate Diethyl phthalate 2,6-Ditert. butyl-p-cresol Ethyl acrylate Ethylbutyl ketone: Ethyl formate Furfural Glycidol Hydroquinone Indene Isoamyl acetate Isobutyl alcohol Isopropoxyethanol REVISIONS (con't): SUBSTANCE " L.P.G. (Liquified petroleum gas) Methylal Methyl n-arriyl ketone Methylcyclohenane MethylcyclohexanoL Methyl methacrylate Nonane Paraffin wax fume Phenol Phthalic anhydride Pindone Propargyl alcohol -Propiolactone Propionic acid Propoxur Pyrethrum Pyridine Quinone Rosin core solder pyrolysis products Rotenone (commercial) Stoddard solvent Sucrose Trimethyl benzene Turpentine VK s P naphtha Warfarin OUSTS TLV SILICA, Si02 Amorphous Precipitated silica from: TO: 5 mg/m3, Respirable dust 10 mg/m2, Total dust 10 mg/m3 f Total dust DELETE RESPIRABLE DUST VALUE Silica gel SILICATES and OTHER DUSTS(m> Graphite (natural) [7782-42-5) from: TO: 5 mg/m3, Respirable dust 10 mg/m3 f Total dust 10 mg/m3, Total dust for material with < 1% quartz.(m) DELETE RESPIRABLE DUST VALUE front: TO: 2. S tng/m3, Respirable dust 5 mg/m3. Total dust 2.5 mg/m3. Respirable dust DELETE TOTAL DUST VALUE 5-30-85 Published by THE BUREAU OF NATIONAL AFFAIRS. INC.. Washington, D C- 20037 C AP00055788 `jp v w r CURRENT REPORT to prove that employer had knowledge of noise levels to which its employees were exposed (No. 93-92!). COURT CASES Smith Steel Casting Company, appeal filed by employer, 5/21/85, 5th Cir., No. 85-4346 (RevComm: Nos. 80-2069 and 80-2322, 12 OSHC 1277). NOTICES OF CONTEST Abesco, Inc., Wheatridge, Colo., is contesting a serious citation and a $350 penalty for 1910.1001(cX2)(m) for failure to protect employees working with asbestos (No. 85-0516). All Phase Electric & Maintenance, Inc., Tampa, Fla., is contesting a repeat citation and a $180 penalty for l926.400(hXl) for failure to equip temporary electrical cir cuits with approved grounding programs. The company also is contesting a serious citation and a $360 penalty for 1926.303(c)(3) for failure to guard abrasive wheels (No. 85-0513). Cargill, lac., Carpentersvilie, 111., is contesting a serious citation and a $630 penalty for Section 5(aXl) for failure to protect employees from danger of fire and chemical explo sion (No. 85-0493). 1037 Larson Woodworking, Inc., Manchester, Conn., is contest ing a serious citation and a $150 penalty for 1910.213<dX 1) for failure to guard table saws (No. 35-0495). Monitor Construction. Portland, Maine, is contesting a serious citation and a $720 penalty for 1925.21(bX2> for failure to instruct employees in safe installation of a person nel hoist (No. 85-0496). Pymm Thermometer, Brooklyn, N.Y., is contesting a re peat citation and a $1,440 penalty for I910.141(gX2) for failure to prevent employees from consuming food and beverages in areas exposed to toxic materials (No. 85-0514), Specialty Polymers, Inc., Leominster, Mass., is contesting a serious citation and a $2,250 penalty for 1910.106(hX7XiX<r) for failure to take precautions to prevent ignition of flam mable vapors (No. 85-0497). Tomahawk Power and Pulp Company, Tomahawk, Wis., is contesting a serious citation and a $720 penalty for 1910.212(aXl) for failure to guard points of operation on feed rolls, and 1910.212(bXl) for failure to guard machinery in conformance with standards (No. 85-0491). Trackmobile, Inc., Lagrange, Ga., is contesting a serious citation and a $300 penalty for 1910.1025(cXl) for failure to protect employees from exposure to lead (No. 85-0512). Full Text AMERICAN CONFERENCE OF GOVERNMENTAL INDUSTRIAL HYGIENISTS REPORT ON CHEMICAL SUBSTANCES TLV COMMITTEE, MAY 1985 Editor's note: The notation "A2" refers to a substance suspected of having a carcinogenic potential in humans on the basis of limited epidemiological data or on the basis of carcinogenicity in one or more animal species. "STEL" refers to short term exposure limits. NOTICE OF INTENDED CHANGES FOR 19a5-fl6 REVISIONS: SUBSTANCE TWA ppm mq/nr^ Acrylamide [79-06-1] from: TO: 0.3 -- 0.03/A2 2-Nitropropeme [79-46-9] from; TO: 10, A2 10, A2 35, A2 35,A2 1,2,3-Trichloropropane [96-18-4) from; TO: 50 300 10 60 5-30-85 Occupational Safety $ Health Reporter ppm STEL mq/nr^ 0.6 20 ,A2 70,A2 75 450 --~ AP00055789 REGULATORY TOXICOLOGY AND PHARMACOLOGY 7, 120-127 (1987) A Scientific Basis for the Risk Assessment of Vinyl Chloride Developedjointly by the Members ofthe Committee on the Evaluation of Carcinogenic Substances, National Health Council ofThe Netherlands' ReceivedOctober 28. 1986 In July 1984 the Minister of Welfare. Public Health and Culture, representing the Dutch government, sent a request to the Health Council of The Netherlands to advise on the health risks preseated by environmental exposure to several carcinogenic substances. One of these substances was vinyl chloride (VC). On the basis of a working document prepared by the Na tional Institute of Public Health and Environmental Hygiene, a committee of the Health Coun cil of The Netherlands prepared a report concerning a health risk assessment of VC which was published in May 1986. A short review is presented ofthe available data and the considerations that formed the basis for the risk assessment ofthc carcinogenicity of VC to humans The advice was based mainly on human data from epidemiological studies of workers occupationally ex posed"to VC. The committee concludes that continuous exposure to 0.001 tng/mJ VC crvrresponds to an additional cancer mortality risk of 10~* per lifetime. The Dutch government con siders this additional risk to the general population to be acceptable. 198? Academic Pro*. IqC. ffN ff INTRODUCTION Man is continuously exposed to a multitude of substances that are present in the environment in which he lives. A number of these substances possess the capability to induce malignant tumors in animals, humans, or both. Some carcinogens are natu rally occurring chemicals and exposure to these can hardly be prevented. Others are man-made, emitted into the environment as a consequence of human activities, and thus exposure can, at least in principle, be reduced to an acceptable level. Reduction of the emission of carcinogens can be achieved by governmental regulation. One of the instruments for such regulation is to set upper limits for pollutants in the environ- ' Committee on the Evaluation of Carcinogenic Substances. G. M. H. Swaen. Department of Occupa tional Medicine, University of Limburg, P.O. Box 616 6200 MD Maastricht, The Netherlands (to whom correspondence should be addressed); A. E. M. de Hollander. Secretary. Health Council of The Nether lands. The Hague. The Netherlands; R. Kroes. Chairman ofthe Committee. National Institute of Public Health, Bilthoven, The Netherlands; L den Engelse. Dutch Cancer Institute. Amsterdam. The Nether lands; V. J. Feron,TNO-ClVO. Toxicology and Nutrition Institute. Zeist. The Nelherlands; G. J. Mulder. Department ofToxicology, University of Leiden. Leiden. The Netherlands; A. L. M. Verbeek.. Department ofSocial Medicine, University of Nijmegen. Nijmegen. The Netherlands: H.G. Verschuuren. DowChemical Europe. Horgen, Switzerland; E. W. Vogel. Department of Radiation Genetics. University of Leiden. Leiden. The Netherlands; A. W. van der Wielen, Ministry of Housing. Physical Planning and Environ ment. The Hague. The Netherlands. 120 0273-2300/87 $3,00 Copyright C 1937 Academic Pres, Inc. AN rights ofreproduction in any form reserved. AP00055790 Chloride taiion of jHands' \g the Dutch >n the health One of these d by the Natealth CounC which was jnsidcrations s. The advice >ationaIly exn1 VC conemment con- iic Praii. loc. present in the . the capability ogensare natuced. Others are , activities, and vel. Reduction ilation. One of in the environ- nment of Occupaicrlands (to whom :l`l! of The NctherInsiitute of Public dam. The Nethermds:G. J. Mulder, -beck. Department uren. DowChemiivrnicy of Leiden, mng and Environ RISK ASSESSMENT OF VINYL CHLORIDE 121 ment that may not be exceeded. These limits are in principle based on qualitative and quantitative information about the carcinogenicity of the specific substance. A particular health risk is then defined as an acceptable risk, which is frequently given as one additional cancer death per one million lives after a lifetime of continuous exposure. This risk will further be referred to as the LO"* risk level. The actual low exposure levels that result in this risk cannot be directly determined and must there fore be estimated by extrapolation. The extrapolation of tumor incidence at high exposure levels to the incidence at low exposure levels is one ofthe principle problems connected with carcinogenic risk assessment. Several mathematical models have been developed to describe the relationship between the level ofexposure to a carcin ogen and the probability of developing cancer, none of which have been verified in real life circumstances. In principle two types of data can be used in an extrapolation model for carcinogenic risk assessment: Data on the carcinogenic response in species other than man from experiments in which animals are exposed to high levels of a carcinogen. Data on the carcinogenic response in humans circumstantially exposed to high levels of a carcinogen, e.g., industrial epidemiologic studies. Animal studies should be performed in a rigorously controlled environment and thus ideally arc not necessarily subject to bias or confounding by extraneous influences. However, the results must be extrapolated from the animal model to man, which introduces a considerable degree of uncertainty. Epidemiology can only study the health effects of environmental or occupational exposures as they actually occur or have occurred. Moreover, epidemiological studies are more likely to be subject to bias or confounding due to uncontrolled differences between the exposed and nonexposed groups that have not been investigated. In addi tion epidemiological studies generally lack precision with respect to exposure data. However, they have the advantage of being actual health effects in humans and thus could provide more relevant information for human risk assessment. Relatively high human exposures to carcinogens may occur in the occupational environment. Epidemiological studies that evaluate the carcinogenic effects of occu pational exposure to particular substances may provide the most significant human data for carcinogenic risk assessment (Cook. 1982; Day, 1985). The purpose of this article is to compare two approaches for carcinogenic risk assessment, taking expo sure to vinyl chloride (VC) as the exposure of interest. Long-term health effects of occupational exposure to VC have been entensively studied; thus VC is a chemical for which a good comparison can be made between the two approaches. An extensive review on the health hazards of VC has been compiled by the Dutch National Insti tute of Public Health and Environmental Hygiene (1984). We will first assess the carcinogenic risk of VC on the basis of animal data. Then we will conduct a risk assessment for VC using human data collected by means of epidemiological studies of workers occupationally exposed to VC. In both types of risk assessment a linear dose-response model has been applied. A linear dose-response relationship is sup ported by the one-hit stochastic model for carcinogenisis, recommended by the American Food and Drug Administration (1971) and by the Dutch National Health Council (1978). The application of a linear dose-response model was also supported by the occupational mortality study conducted by Weber el al. (1981). In this study a subanalysis was undertaken in which the VC exposed cohort was subdivided into AP00055791 122 COMMITTEE ON CARCINOGENIC SUBSTANCES TABLEl Incidences of angiosarcomas inthe Experiments of Maltoni etal. (1981) with SpragueDawley Rats after Various Concentrationsof VC Expt vc concentration (ppm) Incidence of angiosarcomas* () Ratio of concentration to incidence BTt BT 2 BT2 BT2 BT l BT 9 BT 15 BTIS 250 200 150 100 50 50 25 10 8.5 f 0.8 5.0 0.8 3.4 7.9 4.2 2.5 29 19 30 125 15 6 6 4 * Hepatic and ejirahepaiic angiosarcomas. several dose groups, in terms ofduration ofexposure. The results of this subanalysis are indicative for the existence of a linear dose-response relationship between the duration of occupational exposure to VC and the subsequent risk of liver cancer mortality. The pharmacokinetics of VC in animals and humans are still not understood well enough to incorporate an estimation of the "biologically effective dose," based on a pharmacokinetic model for saturable metabolism, in the dose-response extrapola tion model, as was proposed by Gehring et al. (1978,1979). Thus this model was not used in the risk assessment of VC. RISK ASSESSMENT BASED ON ANIMAL DATA VC is a procarcinogen which requires metabolic activation through the cyto chrome P-450 system to exert genotoxic properties (Ivanetich et aL 1977). Muta genic activity of VC has been demonstrated in both in vitro and in vivo assays (Bartsch and Montesano, 1975; IARC, 1979). In several animal studies the animals exposed to VC by oral dosing developed more tumors than the control populations (Maltoni et al., 1981; Feron et al., 1981). There can be no doubt that VC is a carcinogen in animals. In several studies with mice and rats a clear dose-response relationship was noted between VC exposure and frequency of angiosarcomas of the liver. A series of studies with Sprague-Dawley rats, performed by Maltoni et a!. (1981), was selected to form the scientific basis for the risk assessment based on animal data because in these studies VC was applied by means ofinhalation and because the results suggested a clear dose-response relationship for angiosarcoma of the liver. The results of the experiments conducted by Maltoni with mice and rats are presented in Table l. A linear, nonthreshold model was applied for risk extrapolation to lower dose levels. The resuits ofeach separate dose experiment were combined by taking the arithme tic mean ofthe incidence per mg/mJ ofVC applied in each experiment The arithme tic mean of the ratios was 29, which indicates that in order to increase the incidence of angiosarcoma by 1% an additional concentration 29 ppm VC must be applied, AP00055792 iwithSprague- Rauo of concentration to incidence 29 19 30 125 15 6 6 4 f this subanalysis ,hip between the < of liver cancer understood well lose," based on a ponse extrapolais model was not "A irough the cytod.. 1977). Mutao assays (Bartsch animals exposed Nations (Maltoni . a carcinogen in relationship was liver. A series of 81). was selected . data because in results suggested he results of the ed in Table 1 A erdose levels, cingthe arithment. Thearithmeisethe incidence must be applied. RISK ASSESSMENT OF VINYL CHLORIDE 123 TABLE 2 Results of Seven Occupational Mortality of Workers with Past exposure to VC Reference Number of exposed workers Total mortality obs/exp SMR Cancer mortality Liver cancer mortality obs/exp SMR obs/exp SMR Tabershaw and Gaffey. 1974 {United States) Weber eiai, 1981 (West Germany) Fox and Collier, 1977 (United Kingdom) Waxweilere/a/., 1976 (United States) Otter <2/.. 1975 (United States) Theriault and Allard. 1981 (Canada) Nicholson and Henneberger, 1984 (United States) 8334 7021 7717 1294 594 451 257 352/467 0.75 414/435.7 0.95 393/521 0.75 136/126 1.08 89/100 59/55 0.89 1.07 79/77 1.10 94/90.6 115/127 1.12 0.91 35/23.5 1.49 20/17.9 1.12 20/13.5 1.48 7/O.S* 12/0.09 4/1.64 7/0.6 0/0 8/0.14 14.0 15.2 2.4 11.5 1.0 57.1 80/85.6 0.93 28/19.7 1.42 10/0.42 23.8 " Estimated. which equals 74 mg/m3 VC. Taking the inverse ofthis ratio, it can be concluded that an average increase of risk of0.000135 of angiosarcoma per animal will be the result ofan increase of 1 mg/m3 VC. In order to adapt the experimental situation to human lifetime exposure, two conversion factors were introduced. The animals in the experi ment were exposed to VC during 20 hr a week. Human exposure to environmental concentrations of VC occur during 168 hr per week, giving a conversion factor of 168/20 = 8,4. A second conversion factor was necessary because the rats were not exposed for 143 weeks, the average life span of a rat, but only 52 weeks, giving a conversion factor of 143/52 - 2.75. The additional risk ofangiosarcoma per mg/m3 VC concentration for a continuous lifetime exposure for one individual was calculated to be 0.000135 X 8.4 X 2.75 * 0.0031 per mg/m3 VC. The proposed maximum level for environmental exposure to a particular carcinogen as formulated by the committee is one additional death of cancer per one million lives, giving a lifetime environmental exposure of 0.00032 mg/m3 VC (I0~6/0.0031). Thus the committee would consider an environmental exposure to 0.00032 mg/m3 VC to correspond to a 10-6 risk level on the basis of animal data. RISK ASSESSMENT BASED ON HUMAN DATA The risk for humans ofoccupational exposure to VC in industry has been investi gated by epidemiologists for gro.ups ofworkers. AH studies used the design of a retro spective cohort study. A group of workers exposed to VC in the past was identified and followed through time to observe the occurrence ofcancer in the exposed group. AP00055793 124 COMMITTEE ON CARCINOGENIC SUBSTANCES Based on national statistics an expected number of deaths from a particular disease was calculated, taking into account the age distribution, length of follow-up. and calender period. By dividing the observed number by the expected number, the stan dardized mortality ratio (SMR) was calculated, which is a measure ofthe relative risk for a particular cause of death resulting from VC exposure. Table 2 summarizes the results of the seven largest epidemiological studies on workers exposed to VC. All studies except one indicate an excess mortality from cancer of the liver and in particular of angiosarcoma of the liver (ASL). Other types ofcancer also showed a tendency to be increased in incidence, but these increases are not consistent. Total cancer mortality, however, is higher in four out of the seven studies. In order to carry out a risk assessment the results of these epidemiological studies had to be combined to obtain an overall estimate of the relative risk. Prior to combining the results, the studies indicating the highest and the lowest relative risk were omitted, because these studies were considered to be extreme results due to random variation. Three studies were regarded as unbiased estimates ofthe true stan dardized mortality ratio. Although the cohort studied by Waxweilerera/. (1976) was probably completely included in the study conducted by Tabershaw and Gaffey (1974), both studies were regarded as being independent estimates of the risk ofliver cancer after exposure to VC. An alternative analysis after omission ofthe study con ducted by Waxweiler et al. revealed similar conclusions. Because the three studies were not ofthe same size, a weight was given to each study according to its size, based on the standard error of the observed SMR. This weight was the expected number squared divided by the observed number, being the inverse ofthe variance. The over all SMR was subsequently calculated by dividing the sum of the products of the indi vidual weight and the SMR by the total sum ofthe weights. The overall SMR for liver cancer mortality obtained in this manner was 13.07, meaning that workers occupa tionally exposed to VC experienced a 13.07-fold risk of dying of liver cancer. The overall SMR for total cancer mortality is L. 14. VC concentrations that have occurred at the workplace have varied greatly through time. Barnes (1980) retrospectively estimated these exposures to have been approxi mately 1000 ppm between 1945 and 1955, between 400 and 500 ppm, from 1955 to 1965; between 300 and 400 from 1966 to 1972; 150 ppm by 1973; and 5 ppm after 1975. Based on these numbers a time-weighted average of 500 ppm for the total exposure period was applied in the risk assessment An important aspect of the occupational exposure to VC and its long term health effects as described in the epidemioLogical studies, is the average duration ofexposure. In the report of the large cohort study of VC exposed workers, conducted in the United States by Tabershaw and Gaffey (19 74), it was stated that the average duration ofVC exposure was 8.7 years. The committee decided that for the risk assessment for the duration of exposure of all three cohorts 8.7 years would be taken. In summary, epidemiological studies of workers occupationally exposed to an average concentra tion of 500 ppm for an average duration of 8.7 years indicated that these workers experienced a 13-fold risk of liver cancer as compared to the general population. Total cancer mortality was 1.14 times the cancer mortality in thegeneral population. Extrapolation to Lifetime, Continuous Exposure A number ofsteps must be taken before the risks existing for workers exposed to 500 ppm vc fora period of8.7 years can be converted into estimated risks oflifetime. AP00055794 articular disease ' follow-up, and umber, the stan'the relative risk gical studies on mortality from >L). Other types sse increases are >ut of the seven epidemiological ive risk. Prior to vest relative risk e results due to ofthe true stanet at. (1976) was law and Gaffey 'the risk ofliver 'fthe study conhe three studies to its size, based vpected number lance. The over:ucts of the indiill SMR for liver vorkers occupaver cancer. The greatly through e been approxin, from 1955 to ind 5 ppm after m for the total ung term health ion ofexposure, inducted in the verage duration < assessment for n. In summary, rage concemrat these workers ral population, -ral population. kers exposed to risksoflifetime. RISK ASSESSMENT OF VINYL CHLORIDE 125 continuous exposure to low concentrations. The first step is to convert the intermit tent exposure occurring for 8 hr/workday to a continuous lifetime exposure. A work week usually consists of40 working hr, whereas a total week consists of 168 hr. There fore a conversion factor of 168/40 = 4 must be applied. This means that an exposure encountered only at the workplace corresponds to one-fourth of the dose resulting from a continuous exposure to the same concentration. The second step is the calculation of the conversion factor for the duration of the time-limited VC exposure experienced by the workers to lifetime exposure to ambi ent air concentrations of VC. The workers studied by epidemiological methods were exposed for an average duration of 8.7 years. Given an average lifetime of 70 years, lifetime exposure results in a 70/8.7 = 8-fold higher dose at equal concentrations. The conversion from 500 ppm during 40 hr per week, for 8.7 years (500 X \ x $ ppm), leads to a lifetime exposure of 15.6 ppm. An estimated SMR of 13.07 will result from lifetime exposure to 15.6 ppm. Extrapolation to the 10 6 Risk Level Extrapolating the effects ofhigh exposures to low concentrations can only be done if certain assumptions are made regarding the dose-response relationship. We will assume a linear dose-response relationship. This straight line is defined by two points. Having identified two points on the straight line, it is possible to express this line by means of a mathematical equation: SMR = l + b X c (in which c is the lifetime exposure concentration). Calculate b from the model: SMR = 1 + b X c, if c = 15.6 and SMR 13.07. Thus, b = 0,774. The dose-response relationship is SMR = I + 0.774 X c. The next step is to express the 10~6 risk level in terms of an SMR. The accepted risk is expressed as one additional death by cancer per one million lives. In The Netherlands 1484 per million people die ofliver cancer (CBS, 1980). One addi tional case would be 1485, givingan SMR of 1485/1484 = 1.00067. By means ofthe above equation for the linear dose-response relationship, the con centration of VC for lifetime exposure can be calculated, resulting in this SMR of 1.00067: SMR = 1 + bx c,c = 0.0008 ppm. A lifetime exposure to a concentration of 0.0008 ppm = 0.002 mg/m3 VC is ex pected to lead to an additional 10-6 risk. However, it can not be excluded that there are other cancer types related to VC exposure, or perhaps cancer unrelated to specific sites. In fact four of the seven epidemiological studies presented in Table 1 showed elevated cancer mortality. The overall SMR of the three studies used earlier for cancer mortality is 1.14 for all types ofcancer. The lifetime exposure concentration remains 15.6 ppm. SMR =1+bxc ifc=> 15.6and SMR= 1.4, then b - 0.009, giving SMR = I + 0.009 X c. In The Netherlands about 250,000 per one million deaths are due to cancer (CBS, 1980). One additional death will then result in an SMR of 250,001/250.000 = 1.000004 SMR = I + 0.009 4 c AP00055795 P7 f DISCUSSION Epidemiological data have rarely been applied in environmental risk assessment. Extrapolation on the basis ofexperimental data as well as epidemiological data suffers from a number ofshortcomings. The main uncertainty of a risk assessment based on animal experiments is extrapolation to humans. Differences in body size, metabo lism, DNA-repair mechanisms, and immunological responses can lead to differences in response to exposures to carcinogens between animals and humans. As pointed out by many researchers on many occasions, the linear, nonthreshold dose-response model is likely to be an oversimplification of the complex process of carcinogenesis. However, no ideal model incorporating relevant biological mechanisms is yet avail able, or will be in the near future. Therefore a simple model ofa conservative nature was considered to be most appropriate for environmental carcinogen risk assessment of VC. The main uncertainty of a risk assessment based on human data is the lack of exact information with respect to the actual past exposures. Application of a linear extrapolation to these two different types of data resulted in two different environ mental exposure limits, being 0.00032 mg/m3 VC based on the experimental data and 0.00 i mg/m3 VC based on human data, which differ only by a factor of 3. Be cause of the existence of extensive human data the committee decided to base its risk assessment on human data. Conseqently, the Dutch Government was advised to take 0.001 mg/m3 VC as an exposure corresponding to an additional risk of one death per million individais exposed for a lifetime as the scientific basis for the development of air quality standards. REFERENCES Barnes, A. W. (1976). Vinyl chloride and the production of PVC. Proc. R Soc. Med. 69, 277-281. Bartsch, H., and MontesaNO, R.(1975). Mutagenic and carciongenic effects of vinyl chloride. Muiai. Res. 32, 93-114. Centraal Bureau voor de Statistiek (CBS) (1980). Atlas van de Kankersterfie in Nederland. Staatsuitgeverij Den Haag. COOK. R.R. (1982). The role ofepidemiology in risk assessment. DrugMeiab. Rev. 13,913-923. Dav, N. E. (1985). Epidemiological methods for the assessment of human cancer risk, in Toxicological Risk Assessment {&. B. Oayson, D, Krewski, and I. fvtunro. Eds.). Vof. II. CRC Press. Boca Raton. FL.. Dutch National Health Council (Getondheidsraad) (1978). Advies inzake de Beoordeling van Carcinogen!' leit van Chemsiche Stoffen. No. 19. Rijswijk. Feron, V. J., HENDRIKSEN. C. F. M- Speek, A. J., T[L, H. P., AND Sprr. B. J. (1981). Life-span oral toxicity study of vinyl chloride in rats. FoodCosmei. Toxicol. 19,317-333. Food and Drug Administration Advisory Committee on Protocols for Safety Evaluation (1971). Panel on carcinogenesis report on cancer testing in the safety evaluation of food additives and pesticides. Toxicol. Appl. Pharmacol. 20,419-438. Fox, A. J.. andColuER. P.F.<1977). Mortality experience ofworkersexposed to vinyl chloride monomer in the manufacture ofpolyvinyl chloride in Great Britain. Brie. J. Ind. Med. 34.1-10. AP00055796 lulled that u the genei-al ! nsk assessment. .NicaMa<-' suffers Asmrn' asedon tiv >. vicrabo- -aJ; .;1`rences :ui pointed -response oogenesis, yet avail.itive nature . assessment is the iack of [on of a linear ierent environ.ocrimental data j factor of 3. Beed to base its risk as advised to take . ofone death per e development of 69,277-281. ,-inyl chloride. Mutat. rland. Staatsuitgeverij 13.913-923. risk. In Toxicological -ess. Boca Raton. FL. ling van Carcinogeni- 1981). Life-span oral irion (1971), Panel on id pesticides. Toxicol. ivl chloride monomer io. RISK ASSESSMENT OF VINYL CHLORIDE 127 GehRIisc. ?. J.. Watanabe, P. G., and Park. C. N. (1978). Resolution of dose-response toxicity data for chemicals requiring metabolic activation: Example vinyl chloride. Toxicol. Appl Pharmacol. 44, 581-591. Gehring. P. J,, WaTanabe, P. G.. and Park. C. N. (1979). Risk ofangiosarcoma in workers exposed to vinyl chloride as predicted from studies in rats. Toxicol. Appl. Pharmacol. 49.15-21. Holmberg, B,, Kronevi. T.. and WiNELL, M. (1976). The pathology of vinyl chloride exposed mice. Acta VelScand. 17,328-342. Hong. C. B,, Winston, j. M., Thornburg. L. P., and Lee.C. C. {1981). Follow-up study on the carcino genicity of vinyl chloride and vinylidene chloride in rats and mice. J. Toxicol. Environ. Health 7. 909924. IARC (1979). Monagr. Eval. Carcinogen. Risk Chem. Humans 19. 377-348. Ivanetich, K. M., ARONSON. I.. AND Katz, I. D. (\ 977). The interaction ofvinyl chloride with rat hepatic microsomal cytochrome P-450 in vitro. Biochem. Biophys. Res. Commun. 74. 1411-1418. Maltoni. C.. Lefemine, G-, Gliberti. A., Com, G., andCaretti. D. (1981). Carcinogenicity bioas- says of vinyl chloride monomer A model of risk assessment on an experimental basis. Environ. Health Perspecr. 41,3-29Nicholson, W. J,, and Henneberger, P. K. (1984). Trends in cancer mortality among workers in the synihetic polymers industry. Prog. Clin. Biol. Res. 141,65-78. Ott, M. G..Langener, R. R-. and Holder. B.B.(1975). Vinyl chloride exposure in a controUed indus trial environment. Arch. Environ. Health 30,333-339. State Institute of Public Health and Environmental Hygiene (1934). Criteriadocumen: over Vinyl Chloride. Lucht, 34. Staatsdrukkcrij Den Haag. TaBERSHAw, I. R,. and GaFFEY. W. R. (1974). Mortality study of workers in the manufacture of vinyl chloride and its polymers. J. Occup. Med. 16.509-518. Theriault, G., and Allard, P. (I98l), Cancer mortality of a group of Canadian workers exposed to vinylchloride monomers. J. Occup. Med. 23,671-676. Waxweiler. R_1., Stringer, w., wagoner, J. K, Ioners, J.. Falk, K.. and Carter, C. (1976). Neoplastic risk among workers exposed to vinyl chloride. Ann. NY Acad. Sci. 271,40-48. WEBER, H., REINL, W,, and Greiser. E. (1981). German investigation on morbidity and mortality of workers exposed to vinyl chloride. Environ. Health Perspect. 41,95-99. AP00051  National Sanitation Foundation 347$ Plymouth Roid P.O. Box 1468 Ana Arbor. Michigan 48106 USA. Telephone: 313-769-80S0 Telex: 753215 NATSANF7VO UD August 29, 1986 Mr* Bert Mason Air Products P0 Box 538 Allentown, PA 18105 Dear Mr. Mason: Per your request of Gordon Bellen, I am sending Berea's RVCM study: "Prediction of Vinyl Chloride Monomer Migration from Rigid PVC Pipe." Also enclosed are the proposed changes of Standard 14 concerning RVCM as submitted to the Council of Public Health Consultants. These changes have since been adopted. If there are any further questions, please do not hesitate to call me. Sincerely MLT:gh/8b/7 Enclosures Research Specialist AP00055798 National Sanitation Foundation MEMORANDUM M?5 Plymouth Rrud P.O. Box 146$ Ana Afbor,Michi|tn 4$]06 U-SA- TeJphont:313-76S>-80lO Telei: 753215 NATSANFKD UD TO: FROM: DATE: SUBJECT: Council of Public Health Consultants William B. Middendorf, Chairperson July 1, 1986 proposed Revisions to Standard 14: Plastics Piping Components and Related Materials Enclosed are proposed revisions to Standard 14: Plastics Piping Components and Related Materials. This review was conducted by the Joint Committee on Plastics for requirements affecting Item 3.3.2 Residual Vinyl Chloride Monomer (RVCM) and Table 1 Chem ical and Physical Analyses. In the review one Joint Committee member submitted a negative ballot. Staff review of the ballot (copy enclosed) determined it to be a policy issue relating to retesting of products not meeting requirements. This response has been provided to the manufacturer and is enclosed for your review. The proposed revision Involves a change of the Maximum Permissible Level for RVCM from 10 ppm to 2 ppm. Attached is the proposal along with supportive reasons This is an Important issue. Our goal is to adopt it into Standard 14 as ex peditiously as possible. Therefore, Immediately following the Council ballot, the proposal will be forwarded to the Board of Trustees for review and adop^ tlon. To help us achieve this goal we have shortened the normal ballot period by two weeks. Please carefully review the proposal and return the yellow copy of your ballot la the envelope provided by July 18, 1986. mb/13/13 Enclosures: Proposed Revisions Negative Ballot and Response Joint Committee Roster CPHC TC Compilation Ballot Forms Return Envelope i AP00055799 PROPOSED REVISIONS TO STANDARD 14 TOR PLASTICS PIPING COMPONENTS AND RELATED MATERIALS 1 psr/1/8 AP00055800 TABLE I CHEMICAL AND PHYSICAL ANALYSES Parameter Maximum Permissible Level mg/L (ppm) Taste Satisfactory 2 psr/1/8 AP00055801 Reason for the Revision of NSF Standard 14 RVQ4 HPL from 10 to 2 ppm Reason: Vinyl chloride monomer (VCM) is a known human carcinogen. The EPA has proposed a maximum contaminant level (MCL) for VCM in drinking water of 1.0 ug/L. In response to this proposed regulation NSF must be prepared to do one of two things: Test for VCM in extractant water exposed to PVC and CPVC pipe to assure that NSF Listed pipe does not impart VCM to water in excess of the MCL, or . Determine that the NSF Standard 14 limit of 10 ppm residual vinyl chloride monomer CRVCM) in the product wall is adequate to assure that water in contact with NSF Listed product will not contain VCM at or above the MCL. If it is not, then revise the RVCM limit accordingly. The preferred choice is to review the RVCM limit and change it if necessary. RVCM measurement procedures are less costly and more precise than VCM measurements. In addition, RVCM in product can be directly controlled in the manufacturing process, VCM in water cannot. A study was conducted by NSF to reconfirm the RVCM-VCM relationship with PVC and CPVC pipe currently marketed. The data were plotted against a theoretical line (Figure 1). The correlation indicated that the model accurately describes VCM migration from PVC and CPVC products currently marketed. 1 -V. 10 M c AP00055802 The relationship between RVCM in the wall of plastics product and VCM In water In contact with the product has been established theoretically and experimentally*. This relationship Is mathematically defined as: \2o 1/2 4D [ (T + To)1/2 - To1/2] Hp r vr' Where: 3 Diffused VCM into water, g/co r Radius of product, cm D Diffusivity of VCM in PVC - 33 x 10*8 cm2/day (@ 37 C) T Diffusion time period, days To - Pipe age before start of diffusion time period, days 3 p - Average RVCM concentration in the PVC product wall, g/cm Important assumptions in this model are: That the diffusivity constant (D) is independent of the concentration of RVCM in the pipe wall, and that in terms of relative concentration (RVCM to VCM) and diffusivity the RVCM concentration will remain constant. (In other words, the amount of VCM leaving the pipe is so small in comparison to the RVCM concentration chat the depletion of RVCM is negligible). The experimental data show these to be valid assumptions for potable water PVC and CPVC pipe. A majority of the NSF Listed product has aged 30 days or more from the time of manufacture until it is in service and In contact with drinking water. Figure 2 shows the relationship between RVCM and VCM A, R, Berens and C* A. Daniels', Prediction of Vinyl Chloride Monomer Migrations from Rigid PVC Pipe, Polymer Engineering and Science, Vol, 16, No. 8, August 1976. 2 AP00055803 for 30 day old product as predicted by the model* The model predicts that product with two ppm RVCM will impart leas than one ppb of VCH Co water which has been in contact with the product for three days. Based on these data and its agreement with the model, it is recom mended that the limit for RVCM In Standard 14 be changed to two ppm. 3 _ L /flllC AP00055804 6 Figure 1 Theoretical line with actual NSF data at 37C and 3 day exposure. * AP00055805 V> CM ?pm) VCM (ppb) Figure 2 Theoretical relationship between RVCM and VCK at 37C, an age of 30 days, and exposure of 3 days. AP00055806