Document 3Ng93KexV8zrXXGqwOG5QB2q3

SHELL OIL COMPANY PRIVATE h CO'TFIDENTIAL -- REFUTE", i MANAGERS -AHACGET2SCDESSA/CIKIZA - HOUSTON <-{ th --MARTINEZ -------V--.-'O--G--U--'--K--E--7--E-S--T- - NORCO date MARCH 10, 1972 kom GENERAL MANAGER - REFINERIES - HEAD OFFICE subject INDUSTRIAL HYGIENE l/i ' On Jannary h of this year, the Occupational Safety and Health LStraticn (OSHA) announced a "Target Health Hazards Program" aimed ^improving vorkplace conditions vhere potential may exist for exposure -of workmen to five toxic substances - asbestos, cotton dust, silica, lead and carbon nonoxide. The prograa will no doubt result in increased atten tion by Department of Labor Compliance Officers to these substances when they perform facility inspections. Informational sheets (Attachment l) ""have already been prepared by OSHA describing these materials, the-hazards associated with them, and control of sane. Specific instructions (Attach ment 2) have been issued to compliance officers regarding sampling of atmospheres to determine if workmen are being exposed to concentrations in excess of that specified in the OSHA Safety and Health Standards. In view of the foregoing, it is likely that any inspection of \ a Shell refinery will include a review of potential employee exposure to asbestos, silica and carbon monoxide. V7e have not included lead since the "Target Health Hazards Program" is concerned only with inorganic lead and exposure of employees to dust or fumes from this material is considered minimal. In addition to asbestos, silica and carbon monoxide, there are certain other substances which also appear to warrant special attention, since they are commonly encountered in our refineries and were among those covered by the safety and health standards issued on May 29, 1971* These standards specify the maximum level at which continuous exposure (eight hours per day) to each of some U80 air contaminants is permissible without using protective equipment. ^ ' Examination of the list indicates some 60 of the U80 contaminants could be encountered in a typical refinery (excluding laboratory facilities). Out of these 60, 12 substances have been selected (see Attachment 3) which we believe are most likely to be involved in any inquiry into how effective our safety programs are in protecting employees from excessive exposure. In designating these specific contaminants, consideration was given to factors' such as threshold limit values, how extensive a material is either used in the refinery or in a process, potential for release to the atmosphere, and whether the substance possesses characteristics vhere its presence in the air would be readily detected at levels below the threshold limit value. Although in cur opinion the exposure levels to refinery employees from airborne contaminants are either well on the safe side or else adequate precautions are being followed involving use of protective equipment, we believe it would be prudent to initiate a program to provide for monitoring ABS-013070 LAM 030460 1 REFINERY MANAGERS Page 2 the atmosphere periodically at locations where the substances listed on the attachment may occur. With the exception of asbestos and silica, sampling for the other materials can be accomplished with conventional detector tubes or other techniques commonly utilized by refinery safety staffs. The analysis for asbestos and silica is somewhat more complicated and we plan to solicit the assistance of industrial hygienists from the Head Office Occupational Safety and Health Department in evaluating exposure of employees to these substances. Initially, such a study will probably be limited to a single location to gain general insight into the severity of exposure. With regard to the other ten substances, we are thinking in terms of all refineries per forming1 measurements quarterly until meaningful trends are established. This initial effort to document existing levels of hazardous substances and thereby demonstrate that typical refinery exposures are below the allowable TLV's is in anticipation of what we believe will be on accelerating program of monitoring by the Department of Labor. Even tually, industrial hygiene programs may have to be expanded somewhat since the Department of Labor has plans for developing detailed standards for many of the toxic substances and harmful physical agents. Presumably, these will be similar to the one presently proposed for asbestos, which was forwarded to refineries hy Manufacturing Engineering vith their memorandum of February 1, 1912. It is expected that in some cases the standards will require development of considerable detailed information on exposure of employees to health hazards. As an adjunct to the proposed program of monitoring outlined above, we have made plans for industrial hygienists from Head Office to survey Wood River Refinery in the near future to determine if some additional action would be-warranted at this time in regard to our industrial hygiene programs. While awaiting the outcome of that survey, we would appreciate your reviewing the attached list and transmitting to this office any comments you have pertaining to sampling for contaminants, plus any additional views which you believe should be considered in regard to further action in the area of industrial hygiene. "l G. Holzman Attachment cc: General Manager - Technical Departments Assistant to the General Manager - Refineries Occupational Safety and Health - Manager Manufacturing Engineering - Manager ABS-013071 LAM 030461 TARGET HEALTH HAZARD FACT SHEETS PREPARED BY THE OCCUPATIONAL AND HEALTH ASBESTOS What is it? Asbestos is a general term used to describe several fibrous mineral silicates that occur as white, grayish or greenish, masses, either compact or of long silky fibers. The mos! important types are: Chrysolite - a simple magnesium silicate; amosite -- a complex magne sium iron silicate; eiocidolite - a complex sodium iron silicate. Some 95 per cent of world asbestos production comes front chrysolite. Where is it? The heat-resistant properties of asbestos have led to many uses -- for example, as protection against fire, as insulation, brake and clutch linings, build ing. materials, as a filter and in plastics. The raw material and end-products are found nearly everywhere. What is the- hazard? More than 200.000 employees face risks from asbestos. The principal danger is caused by inhaling asbestos fibers. Recent studies have shown the presence of asbestos fibers in the lungs of persons having no industrial exposure -- probably due to their presence in the atmosphere near construction sites. Prolonged inhalation of asbestos fibers between 5 and 50 microns {one-millionth of a meter) long can produce a lung disease known as asbestosis. The lungs cannot eliminate asbestos fibers, so the fibers coat the tissues. If this process continues over a period of 10 to 20 years, with significant quantities of asbestos present, the tissue reaction prog resses until a generalized, diffuse fibrosis occurs, causing severe respiratory disability. There have been reports of increased incidence of lung cancer in persons with asbesJosis. IIow it is controlled? Enclosure and local exhaust ventilation applied to equipment and/or operations arc the principal means of preventing employee exposure to dangerously high concentrations. U.S. bureau of Mines-appsoved dust respirators may be worn by employees as protection for some operations. What are approved levels? CSHA's permissible level is 5 fibers per miliiliter greater than 5 microns in length for an eight-hour, time-weighted, average airborne concentration. *lTiis may be increased to 10 such fibers per milliliter for no more than 15 minutes per hour, up to five hours per eight-hour day. Imminent danger situations are generally not applicable. Any exposure greater than permissible levels for unprotected or improperly protected workers is considered a serious violation. How is it measured? Asbestos dust will be collected with a persona! sampling pump. Fibers will be counted microscopically at 400-450 magnification using phase con trast illumination. COTTON' DUST Where is it? Colton dust occurs throughout the textile industry and affects cotton. Ilex and soft hemp workers. Trie greatest exposure to cotton dust generally occurs doting the carding of cotton - an operation that combs out cotton fibers and sets them parallel by drawing them between toothed cylinders. However, machinery through out the cotton mill must be cleaned frequently, and much exposure to cotton dust occurs then. What is the hazard? More than S00.00D employees in cotton processing operations of all types arc exposed to cotton dust. While the exact effects of cotton dust are not known, prolonged exposure to heavy air concentra tions can cjuse a disabling lung disease know:', as byssinosis. Materials adhering to cotton fitters, such as unwanted leaf, stem and boll trash, when inhaled, elicit an allergic reaction or response. Byssinosis generally ad vances through three recognizable stages. The firs: is commonly called "Monday fever" and begins only after exposure of more than 10 years. Workers develop a:: irritating cough, tightness of lire chest and breathlessness. The attacks usually come on Monday, or after a period of absence from the plant and last only a day c: so; lienee the name "Monday fever." In the second stage, the:.; symptoms extend over more days in the wee!; and finally become permanent. If exposure to cotton d.c-t is ended at this stage, recovery can occur. In lire third stage, the tightness of the chest and labored breathing become ro distressing the worker must leave the industry. The dis ease can progress then to cluonic bronchitis and emphyse ma. How is it controlled? Enclosure of machinery in cl! operations and local exhaust ventilation are the rimcipa! means of preventing employee exposure. Pretrectm.eut of the cotton in early processing stages may also be helpful. What are approved levels? OSli's permissible love- is 1 milligram per cubic meter of air for an eight-hour, time-weighted, average airborne concentration. Imminent danger situations are generally not applicable. Concentra tions of 3 milligrams per cubic meter, are considered serious violations; concentrations between 1 and 3 milli grams per cubic meter for' an eight-hour, time-weighted, average, are considered regular or nonserious violations. How is it measured? A persona! sampler is attached to a workman's clothing with the uncovered filter facing down, usu. ally for a six-hour sample. SILICA What is it? Silica is an oxide of silicon and is the characteristic ingredient of a great variety of minerals, including quartz, cristobaliie. tridymite, amethyst and sand, h is widely used in cores for metal casting opera tions, ceramics, decorative materials, insulation, building materials and glass. Where is it? Silica is found throughout industry in various manufacturing processes, such as iron and mineral processing plants, mining, abrasive soap p-x.Ja.tii.-n. glass manufacturing, potteries, foundries, abrasives use and manufaclurinci in stone cutlmii arid finishing industries. Occupotionol Sofety f. Heolfh Reporlor ABS-013072 LAM 030462 iiii.u is n.t..a:u: mu:; i.J iNimuii v uipiiivco arc exposed lo the hazard erected by inhalation of silica oust, Inhalation of these panicles cjii piuduec lapiuiy-de- veloping (acute) or dironic silicosis - a disabling lung disease. Typically, the lung tissue reads to the presence of silica jar tides by forming fibrous matter around the particle. 'Evidence suggests that particles below one micron (one-milliontlt of a meter) in size may be the most dangerous since ihey may penetrate deeper into the lungs - in high concentrations. In rapidly-developing silicosis, symptoms appear eight to 18 months after the first exposure. Chronic silicosis, the type usually en countered in industry, generally, is produced only after years of silica inhalation. The symptoms for either type are the same - slowly increasing difficulty in breathing under cxerlion. In some workers, large masses of dense fibrous tissue develop in the upper portion of the lungs, leading to severe respiratory crippling. Tuberculosis is a frequent complication of silicosis. IIow is it controlled? The best method is substitution of another material; for example, use of steel shot or alumina grit in place of sand-blasting operations. Other methods include enclosure of operations, local exhaust ventilation, segregation of operations, wetting, and ordi nary good-housekeeping practices. What arc approved levels? For icspirablc quart/, particles, OSllA's permissible level is 10 milligrams per cubic meter of air, divided by the per cent of free silica plus 2, as shown in tins formula: 10mg/ni:*. %Si0j+j For respirable cristobalite and tridymitc, the limits are one-half the value for quartz. Imminent danger situations generally arc not applicable. Any eight-hour, timeweighted average greater than four times the limit is considered a serious violation. Exposure to concentrations between llte limit and four times tiie limit are considered a regular or nonserious violation. How is it measured? Personal sampling pumps with filters arc used to collect dust samples for worker ex posure. The collected dust then is weighed for a given volume of air. Similar procedures are used to determine the percentage of silica in the air. quantities, me icsuit r. me same -- severe rasiromiesur si. blond and central nervous system disorders, tribulation of lead dust or fumes is the must frequent means o! to'.-.? and results in most of the industiLl health prob!.;::i involving this metal. Lead is a cumulative poison. A part of a small daily dose is not eliminated, but is stored in the. body. F.ventually. a point is reached whee symptoms and disability - even death -- occur. How is it controlled? Since the primary route of industrial lead poisoning is inhalation, enclosure and local 'exhaust ventilation are tiie principal means of control. Daily wet or vacuum cleaning of ail lead dust, personal hygiene, prohibition of food and beverages in the work area and use of U.S. bureau of Mines-appioved respirators aie other means that can help control exposure. What are approved levels? OSH.Vs permissible level is 0.2 milligrams per cubic meter of air for an eight-hour, time-weighted, average aiiborne concentration. Imminent danger situations arc not generally applicable. .Any ex posure above 0.6 milligrams per cubic meter cf air to: an eight-hour, time-weighted average is considered a serious violation. Levels above 0.2 and less than 0.6 are con sidered regular or nonserious violations. How is it measured? The atmosphere is sampled with personal sampling pumps and filters for a minimum! of 60 minutes. Filters then are weighed to determine concentra tions. CARBON MONOXIDE What is it? Carbon monoxide is a colorless, almost odorless, tasteless, nonirritating gas. It is produced by the incomplete combustion of fuels, such as wood. gas. coal oil and gasoline. Misters refer to it as ''white damp". I: also is commonly called "coal gas". What is it? Carbon monoxide is found anywhere car bonaceous fuels arc used. It can be found in everyday activities as well as in industrial situations -- near in correctly vented gas heaters, near gasoline-powered ma chinery and around automobiles run indoors: blast fur naces; and catalytic reduction operations. What is the hazard? Because it is found so videiy. nearly everyone, at- one time or another, is exposed to LEAD What is it? Lead is a soft, dense, malleable, heavy metal with a low melting point. It is gray in color and, because of its characteristics, has a wide application of uses. Where is it? Lead is used to make printing type and plumbing, shield telephone and power cables and to protect against radiation hazards. As an alloy, lead mixed with steel makes excellent bearings. As solder, lead alloy is vital in the electrical and electronic industries. Lead compounds are used to make paints and ammunition, and lead oxides arc used in car batteries. What is the hazard? More than 1.6 million employees in nearly every industrial manufacturing process and in many service industries are cxjwsed to the poisoning effect of lead. Lead can enter the body by inhalation, absorption through the skin or by ingestion. In sufficient carbon monoxide. The danger lies in inhalation of gas. Carbon monoxide enters the blood stream through the lungs in the same manner as oxygen, but i: displace? oxygen in the blood because it lias approximately 210 times greater affinity for hemoglobin in tire blood than oxygen. As a result, the blood cannot transport oxygen, causing suffocation even in an atmosphere containing ample oxygen. Over a period of time, as httle as 700 parts per million of carbon monoxide v.ili saturate 50 percent of the blood hemoglobin -- while a few breaths at concentrations of 10.000 parts per million may cause 60 to 80 percent saturation and death. Fortunately, regard-, less of how high the percentage of saturation of the blood has been, practically all carbon monoxide is eliminated by the body within 8 to 10 hours after exposure ends. How is it controlled? In general, adequate ventilaiic-r. will prevent carbon monoxide poisoning, bnch.sa:.-. gen eral or dilution ventilation and local exhaust sentdatio::. t Copyright 1972 by THcr Bureoo of Nclionol Afloirs, Inc. ^ ABS-013073 LAM 030463 ..... ~ -Oj'wjutu lO "gcrous- concentrations. Automated da lection ala mi sys- ' ICiViS e; so <ue useful control measures. WJtalI -arc approved levels? OSHA's permissible level is 50 pa:is per million parts of air for an eight-hour, lisne-v/trighted. averapc airborne concentration. Co.tceiitra* tiou aliove 500 parts per million for any length of time arc ct>: isideied to be imminent danger situations. Con- tiour or more arc considered to he serious violations. Concentrations above 50 parts per million, but below 150 parts per million for an eight-hour, ti.me-v.eiehted aveiugu are considered regular or itonserious violations. How is it measured? Tire primary method is a carbon monoxide portable. Hopcalite-reagcnt type ineicr. The secondary method is certified detector lubes. ABS-013074 LAM 030464 PREPARED BY THE OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION OSHA SAMPLING DATA SHEET NO. 1 Sul'Huncc: bon monoxide. Standard: 29 CFR i9!0.93(b) Table G-l, of August 13. 1971 8-hour lime-weighted average: 50 ppm (55 mg/mJ). Sampling Equipment: (1) CO meter. (Pen table, Hopcalite -- reagent type) - Follow directions. (Primary Method) P'S Certified or NiOSH approved detector tubes and a hand operated pump (not squeeze bulb) may be used for compliance purposes. (Secondary Method) .Analytical Procedure: (1) Direct rending instrument based on measurement of Jieat of reaction produced by oxidation of CO to COj. Fo!iow instructions. (2) Detector tub's are read for length of stain, strokes of pump are noted and appropriate corrections made for pressure (or altitude) above 5000 feet (1500 in). The lubes are not to he used when below 0 degree F (-IS C) oi above 125 degrees !' (52 C). Sampling Period: (1) Hopcalite: maximum feasible number of readings should he averaged to determine average exposure. Time required dependent on variability and cyclical nature of exposures. (2) Detector tubes: direct reading, leiigth-of-stain detector tubes (certified on NIOSH approved) may be used for compliance purposes, if at least one sample per hour is taken per exposed worker or close group of workers. In an 8-hour day more frequent samplings per hour are preferred, especially for exposures over 50 ppm. Eight different samplings (one per hour is considered the minimum acceptable number). Imminent Danger Situations: Concentrations above 500 ppm (10 x TLV) for any Jength of lime'are considered to be an imminent danger. Serious Violation: Concentrations above 150 ppm (3 x TLV) for a total of 1 hour or more in an 8-hour workday are considered serious. Honserious Violation: Concentrations above 50 ppm, but below 150 ppm for 2n 8-Iiou; time-weighted average arc considered nonscrious violations. Dc Minimis Violation: Kot applicable. Standard: 29 CFR 1910.93a(a) of December 7, 1971 8-hour time-wcighlcd average*: 5 fibers per milliliter greater than 5 microns in length. Excursion limit*: 10 fibers per milliliter, up to 15 minutes in an. hour for up to 5 hours per S-hour day. ^Unprotected or improperly protected worker ex posures.- Analytical Method: Fibers counted at 400-450 magnification, using phase contrast illumination, with sample mounted in highviscosity solution of membrane filter material. Sampling Equipment: Personal sampling pump plus Millipore type AA filter (37 mm, 0.S micron pore size). Face cap is removed and filter used open face during sampling. Sampling rate: 2 1/in. Sample Size: Minimum period of 15 minutes for evaluation of excursion limit. Several samples of up to 4 hours for evaluation of 8-hour average. Samples with a visible deposit may be too heavy to count. Compare with a clean filter. Heavy concentrations of visible dust in the air (100 to 500 fiber s/ml) may require short sampling periods of only 5 minutes, or less. Blanks: With each batch of samples submit two filters which arc subjected to exactly the same handling as for tha samples except that no air is drawn through them. Labei these as blanks. Shipping: The cassettes in which the samples are collected should be shipped in a suitable container, designed to prevent damage in transit. Imminent Danger Situations: Generally not applicable. Serious Violation: 5.1 or more fibers per ml, greater than 5 microns in length, for an unprotected or improperly protected work er, for an S-hour time-weighted average, except for certain proven excursions as noted in the emergency standard, which may raise the S-hour time-weighted average to 5.S fibers per ml. Nonscrious Violation: Not applicable. . Dc Minimis Violation: Not applicable. OSHA SAMPLING DATA SHEET NO. 2 Snbstance: Asbestos. OSHA SAMPLING DATA SHEET NO. 3 Substance: Crystalline silica. Occupofionol Sofcty & Health Reporter ABS-013075 *r LAM 030465 Form Quartz (respirable): Ciislol'alitc: One-half the value for quartz Tridytnac: One-half the value for quartz 10 nrp/m3 %Si02 + 2 A nalytical Method: Gravimetric personal samples for worker exposure should be larcd and rcweiglicd by DOL on a Cahn balance. The percent of free silica is determined by NIOSII on the fixed location sample using a colorimetric wet clicmicrl method, minimum detectable amount: 0.01 mg/filtcr. Sampling Equipment: For vvoikcr exposure: Personal sampling pump plus p reweighed MSA type FWS-B or Gelman type VMI filter, using 2-piece filter cassette and 10 mm nylon cyclone. Two filters should be subjected to the same handling as the samples except that no air is drawn through them, and these should be used as blanks. Sampling rate: l.S J/m. For determining % quartz: Collect at fixed locations near workers. using NT OS! I prcwcichcd MSA type FWS-B fillers in 3-piece cassettes plus Cast 1531 pump with 9 1/m critic?* orifice and J/2 inch steel cyclone. The vacuum release valve should be adjusted to 10-15 in. Hg suction. Two blanks of tiic same filter type should be submitted with the sample. Sampling rate: 9 I/m. Sample Size: Minimum: 4 hours. Maximum: S hours. Shipping: The cassettes in which the samples for determining % quartz arc collected should be shipped- to NlOSil in a suitable container, designed to prevent damage in transit. Imminent Dinger Situations: Generally not applicable. -. _ Serious Viobtior:: Any 8-hour time-weighted average greater than 4 x stated TLV value. Nonserious Violation: Any 8-hour time-weighted average between the stated TLV and 4 x that value. De Mininiis Violation: Not applicable. OSHA SAMPLING DATA SHEET NO. 4 Substance: Lead and its inorganic compounds (except lead ar senate). Standard: 29 CFR 1910.93(b), Table G-2 of August 13, 1971 & ANSI Z37.11-1969 S-hour time-weighted average: 0.2 mg/m5 Analytical Method: Atomic.absorption. Detection Limit: 0.0003 mg/filter. Sampling Equipment: Personal sampling pump plus unweighted 37 mm Milli- porc type UA filter. Either 2- or 3-piece, filler cassette Sample Size: A minimum sampling period of 60 minutes is recom mended, anu longer periods, up to full shift, are prefer able. Care must be taken to prevent materia! from failing off heavily loaded filters during shipment. Tins rnay be done by placing another filter on top of the one-with the sample, exercising care not to dislodge any of the sample in the process. Blanks' Witls each batch of samples, submit two fibers which are subjected to exactly the same handling as for the samples except that no air is drawn through them. Label these as blanks. Shipping: The cassettes in which the samples arc collected should be shipped in a suitable container, designed to prevent damage in transit. Imminent Danger Situations: Generally not applicable. Serious Violation: Anything above 0.6 nrg/m3 for an S-hour time- wciglued average. Nonscrious Violation: Anything above 0.2 mg/m5 and less than 0.6 mg/m3 for an 8-hour time-weighted average. De Minimis Violation: Not applicable. OSHA SAMPLING DATA SHEET NO. 5 Substance: ~ Cotton dust (raw). ... Standard: 29 CFR 1910.93(b). Table G-J of August 13, 1971 8-hour time-weighted average: 1 mg/m3 Analytical Method: Net weight of gross airborne dust, using balance with sensitivity of 0.01 mg. , Sampling Equipment - Personal Samplers: Cotton is to be determined primarily with the persona! sampler attached to the workman's clothing with the face of the filter pointing down. The filter should not be covered. Our experience is that at least a 4- and prefer ably a 6-hour sample (at 1.5 1/m) is required in a textile plant,opening or carding area to obtain reliable results. A preweighed filter (0.01 mg) should be used and reweighed to the same accuracy. There is no ceiling or arty limit on excursions. Because of the nature of both the sampling method and the development of byssinosis. it is neither desirable nor possible to get grab samples. Sampling Equipment - General Work Area: Preweighed Gelman VM-l or MSA type FWS-B 5 micron pore size filter in 3-piece cassette, located in the general work area with the cap removed and 'the filter facing down. Suction provided by Gas! 1531 pump with a 7.4 1/m critical orifice. The vacuum relief valve should be Copyright 1972 by The B-^rccu ot Moliooot Affairs, Inc. ABS-013076 V' LAM 030466 iu-ij in., i ig, suction. Sampling rale: 7:4 '1/in for recommended i:ii:iiiTnsm of 60 minutes. Long:: period samples up lo full sliifl arc preferable. Litters should not be so heavily loaded that the sample is dislodged in transit. Blanks: With each batch of samples collected, two additional filters should be subjected to exactly the same handling except that no air is drawn through them. These should be used as blanks. Shipping: The cassettes in wltich samples ate collected should be shipped in a suitable container, designed to prevent damage in tiansit. imminent Danger Situations: Generally not applicable. Serious Hazard: An S-liour time-weighted average above 3 mg/m3 for identified worker. 3 x TLV. Nonserious Hazard: An 8-tiour time-weighted average above 1 mg/m3 2nd below 3 mg/m3 for an identified worker. Dc Minimis Violation: Not applicable. ABS-013077 LAM 030467 Attachment 3 AIR CONTAMINANTS PROPOSED FOR INCLUSION IN MONITORING PROGRAM Substance Asbestos Benzene Carbon Monoxide Hydrogen Fluoride Hydrogen Sulfide Mercury Methyl Ethyl Ketone Phenol Silica Sulfur Dioxide Toluene Xylene Threshold Limit Value ppma) ng/M3bT~ c) 25 80 50 55 32 10 25 - o.ia) 200 590 5 19 e) 5 200f) 100 3.3 , 750^) b35 a'Parts of vapor or gas per million of contaminated air by volume at 25C and 760 mm. Hg. pressure. ^^iMilligrams of particulate per cubic meter of air. c)Covered by a special, emergency standard issued December 7j 1971 which bases threshold limit on maximum of five fibers per milli liter greater than five microns in length, rather than on ppn. A proptpsed permanent standard recommends same TLV level. % _ ^Change to 0.05 mg/M^ is proposed. e)Quartz = 10 mg/M^ J&202+2 Cristobalite or tridymite: One-half value for quartz. ^Change to 100 ppm and 375 mg/M3 is proposed. ABS-013078 lam 030468