Document KJk2pBOw3e9yawKYN3ozeM0go

R&S 108133 0 '*'3S,S>~teDlCAl PBSBA3CH OH 70BH 63 69 000017476 cE.rd s > --t* year as-1961- {Right justify [Numeric only] Author(s), as Last Kane PS (No Punctuation) and coder for journal as JAKA preceeded-by. one blanb space 11 73 //q Sub-In deal Code Title of Retort; end vith space-hypben-hyphanyspace. Police vith Index: Terrs, separated iron each other vith -coma-space. Avoid other punctuation; do'not abbreviate. iy *.* . v . 61 62 //C X, ^Oc/ </U.S-J fasl T^fp 21 22 23 24 Source (Journal, Vol., Number , Pages, Date ) 12 d X1~/r. / J /9 "7C. iA 5^e (Pc.-// i.'c_S * ` --7 z^---u--------- r~ 61 62 . iTi 32 Brief Sumarv' 61 62 61 62 63 6A G0G0174 Environmental Health Perspectives Vol. 17, pp. 107-115, 1976 PUC: Health Implications and Production Trends by Myra Karstadf R&S 108134 Poly ( vinyl chloride) (PVC) is a complex plastic system. Individual components of the PVC system, including residual vinyl chloride monomer (ICVC-M) and certain additives, may pose risks of harm to human health. There have been significant reduc tions in the UVCM content of PVC resin since 1974, reducing the cancer risk of work ers in PVC fabrication plants and consumers of PVC products. A "no-effect" level for vinyl chloride monomer (VCM)-induced carcinogenesis has not been found to date; therefore, the significance of human exposure to low levels of UVCM remains to be determined. Exposure to PVC dust may cause pulmonary dysfunctions. Pulmonary and other possible health effects of PVC dust require further study. The PVC plastics system should be characterized as to interactions among its various components and as tu interactions of the components and the PVC system as a whole with biological systems. In January 1974, B.F. Goodrich Chemical Company announced that three reactor workrs in a poly (vinyl chloride) (PVC) polymeriution plant had developed a rare cancer, angio.ureoma of the liver. Exposure to vinyl chlo ride was linked to development of angiosarwma of the liver by subsequent epidemiological tuulies. Animal studies, several initiated be fore the B.F. Goodrich announcement, also link exposure to vinyl chloride (VCM) with development of cancer. Regulations promulgated in the United States of America since early 1874 have refjlted in the lowering of VCM concentrations m the atmosphere of PVC manufacturing rlants, and decreased concentrations of VCM :n PVC resin. This has reduced the cancer risk if PVC production workers, workers in PVC fabrication plants and the ultimate consumers 1 fabricated PVC products. We are now at a crucial stage as regards studies of the effects of plastics and plastics components on human health. Human expo`ure to massive doses of VCM, whether due to au-mUrolled venting of PVC polymerization or the voluntary venting in a home Uthroom of tin aerosolized VCM hair spray, is rwntiaily over. The time has come for study d possible health hazards posed by the com- : plastic system called PVC. '.'iiiiia V;m NVss, Washington, 11.C. 2DOOS. Why be concerned about PVC? A publica tion (/) states that: "Total world employment in the VCM and PVC producing industries is likely to be well over 70,000 workers. Those employed in industries which use PVC as a basic element are likely to total in the millions. Those who come in contact with PVC every day in some form or other probably make up about at least one-third of the human race." What are the human health effects of PVC? There are several components of PVC which, on their own, could affect human health ad versely: VCM, PVC dust considered as a dust, additives of various sorts. ("Additives" for our purposes includes stabilizers, colorants, flame retardants, plasticizers, fillers, etc.) But one cannot consider the components of PVC solely as independently acting potentially toxic agents. PVC is a complex chemical sys tem with little-understood interactions, both physical and chemical, among its components. Leaving aside the multicomponents inter action problem for the time being, consider the individual components of PVC which may pose risk of harm to humans. VCM is already identified as a cancer-causing agent. Even given the reductions of VCM in PVT rosin, which have been achieved . by changi s in both production and compounding procedures, some RVCM(residual vinyl chlo ride monomer) is still present in PVC. October 1976 107 Table 1. April 1975 status of suspension resin stripping,* Company A* Bh C D E _---------------- F G H I Number of suspension resin grades -- -- 5 -- 13 15 4 (Homopolymer) 4 (Copolymer) 4 -- Suspension resin production, C'r 60 40 100 100 80 20 86.8 5.4 3.8 3.2 .8 100 6 14 80 16 84 100 38 9 25 5 15 8 RVCM, ppm 2000-4000 4000-6000 2000-5000 <400 400 500-700 0-50 100 600 1000 4000 <400 1500 2500 100 300 400 2000-10,000 400 600 800 1800 3600 4000 `Based on data from responses to 3/31/75 section 114 request (4). 'All suspension resins to be reduced to <400 ppm RVCM by 7/75. c Some values are speculative until improved stripping is installed. In 1974 Rowe (2) estimated the average monomer concentration of PVC resin to be approximately 1000 ppm. As shown in Table 1, RVCM concentrations of 100 ppm or less for suspension resins before compounding were not unusual by April 1975. An advertisement (3) run in July 1975 by a major manufacturer of PVC stated that general-purpose PVC homo polymers and blending resins were being pro duced with a maximum of 10 ppm, and usually less than 5 ppm, RVCM.* Tables 1-3, taken from a U.S. Environmental Protection Agency (EPA) publication (4) * The advertisement states (in part): "At Tenneco, we've developed a unique new production technology that allows us to produce our general purpo-e PVC homopolymer, blending and dispersion resins with no more than 10 parts per million of VCM(vinyl chloride monomer). In fact, the typical VC.M content of these homopolymer and blending resins is less than 5 parts per million and under 3 parts for our dispersion resins. And. we are producing our flexible compounds at nondetectablc(le*s than 1 ppm) levels. "This is a 98',i to 09'P reduction from what was once the typical practice of the industry for residual VCM," give some idea of the present RVCM in several PVC resins. In particular, note company E in Table 1- S6.SU of suspension resin production is said to be at 0-50 ppm RVCM (with a foot noted qualification that "some values fire spec ulative until improved stripping is installed".) Note also that for company A, 60(< of whose resin had a RVCM concentration of 2000-1000 ppm in April 1975, with the remaining 40rc at -1000-6000 ppm, "all suspension resins (were) to be reduced to less than 400 ppm RVCM by 7/75." Health problems which may be associated with RVCM in finished PVC resin are of im portance to workers and consumers. The resi dual VCM in the old high-residue PVC evi dently posed problems for workers in fabrica tion plants. Data collected by the United States National Institute for Occupational Safety and Health (NIOSII) indicate that several angio sarcoma cases were identified in fabrication plant workers in this country and abroad (Table 4) (5). R&S 108135 10S Environmental Health Perspectives Table 2. Suspension resins. ASTM cell class *1 CPI-20250 CP2-ii;:uo CP3-153-10 GP4-15340 (JPG-15343 UP1-14443 CP2-14443 CP3-15433 GP5-15433 CPC-13433 Copolymers Cll-8500 Cll-3500 Prod, 'l 5 - "5 13 35 24 0 1 1 5 9 1 1 VCM into stripper, ppm (40-GO) X 10` (40-00) x 101 (50-70) X 10* (G0-90) x 10* (90-120) X 103 (80-100) x 10' (80-100) X 10' (80-100) x 101 (90-110) x 10` (100-140) X 103 (40--GO) x 103 (90-110) X 103 ppm (avg.) VC1I out of stripper (dry basis), 3,050 2,050 1,200 1,050 950 600 550 500 450 450 2,100 1,000 *ASTM cell class is standard definition of resin (ASTM-D-1755). 1 Based on limited data (less than three samples) (4). VCM out of dryer, ppm (avg.) 308 1G2 104 95 82 25 IS 21 15 18 280 95 Emission factor, kg VCM 100 kg PVC 0.27 0.18 0.09 0.09 0.08 0.05 0.0G 0.05 0.05 0.05 0.18 0.09 , NIOSIT tin tit (Tabic 5) presented in late 1 (tin) indicated that breathing zone sam- ^Pes in fabrication plants turned up relatively low concentrations of VCM-even at a time when UVCM concentrations were high com pared to today's values. Even at that time, as Wagoner put it: "(>()'/ of the samples were less than 1 ppm" {lilt). This level (1 ppm) is the maximum exposure level (8-hr time- j weighted average) currently permitted by the , United States Occupational Safety and Health 1 Administration (OSHA) standard (?). Again quoting Wagoner {Ob) : ``I think it [the occur rence of angiosarcoma of the liver in fabrica tion plant workers] points to the possibility of low level exposure being obviously very haz ardous." A recent contract study (S) prepared for NIOSH reported on fabricating plant VCM concentrations in 11)75. The VCM concentra tions are, in a number of cases, very low (loss than 0.01 ppm, the limit of detection). How ever, certain work stations had values which Table 3. April 1975 status of dispersion resin stripping with protection of future capabilities.* riant Current RYCM, after stripper ppm in product Projected RYCM Time to implement controls after stripper, ppm needed to meet projected levels, months A 30,000 B 50,000 1-3 20,000 5 10,000 C 20,000 5-15 4000-G000 D 1500-4000 -- -- E 15,000 1-10 6000 F 13,000-18,000 10 4500 500-1000 G 2000-10,000 25 2000 400 m 14,000-18,000 2000 5-30 <1 1200 -- (--------------------------------------------------------------------------- | `From responses to March 31, 1975, section 114 request (4). 6 ,6 48 -- 12-18 30 42 30 48 30 -- B&S 108136 October ll'Tfi 1011 l-- OO! OO R&S 108137 * Table 4. Reporter cases of angiosarcoma of the liver among nonpolymerization workers expvscd to vinyl chloride. Country C se Birth date 1st VC Diagnosis of or PVC angio exposure1 * * 4 sarcoma * Time from Tot Age 1st expo expo* at sure to diag Sll VGt diagnosis nosis, yr yr Date of death* Fed. Rep. Germany Fed. Rep. Germany 0 Great Britain Ok Italy 01 Sweden 02 United States---------- - 14 United States 15 07-10-30 75-00-30 OS-14 7-34 ; -li Oi 13 00-Go -25 09-09-52" 00-00-60" 00-00--iGf 00-00-G5f 00-00-45 01-13-3S1 00-00-00k 03-00-73` 02-00-70` 04-19-71e 05-15-72c 00-00-73' 07-00-72' 43 38 55 3G 01 60 47 21 14 10-10-71 14 03 12-10-71 24 11 12-00-70 G 3 04-10-71 27 23 08-10-77 30 00 07-03-73 00 00 02-15-73 1 ``00'' indicates unknown data. b Loading pesticide cans with VC propellant. `Microscopically confirmed angiosarcoma of the liver. 4 Assistant factory chemist. Pouring PVC o'1 ixture onto fabric bases. 1 Production of P . ^ sacks. `Angiosarcoma involving liver, lung, and pericardium. Although difficult to determine, primary site seems to 1m pericardium, h Production of vinyl chloride. 1 Machine operator covering electrical wire with PVC plastic insulation. 1 Diagnosis: sarcoma (possibly "angiosarcoma"), liver. Possibility of generalized neoplasm of the reticuloendo thelial cell system cannot be ruled out. k Accountant at plant making PVC fabric. exceeded the 1 ppm 8~hr time-weighted average currently permitted by OSHA. How low must you go before RVCM ceases to represent a ha?."'-'" "fTect" level for VCM carcino ?en found to date; car- all groups of anir- *w., concentrations of inhaled VCM. Just how low are the VCM co centrations in fabrication plants now? Publi cation of monitoring data would be useful for j analysis of possible risks of harm to health. A fabricated PVC product category with wide consumer exposure is PVC automobile upholstery, rooftops, and interior fittings. The Table 5. Summary of VCM concentrations in PVC fabrication facilities. Type of plant Firm and mold (7 plants) NIOSII data Breathing zone samples Area samples Source samples Pipe and mold (2 plants) Industry data Breathing zone samples Area samples Source samples Maximum 12 S 340 <10 35 540 Minimum <0.3 <0.3 <0.3 <0.1 <0.1 <0.1 Mean 3 1.2 18 <1 G 142 Fraction >1 i ppm ; 2/5 1/11 10,21 4.21 1G/20 10-T7 110 Environmental Health Perspective;: EPA lias a contract study, entitled, ``Sampling of Automobile Interiors for Vinyl Chloride Monomer" (9) in progress. According to Hedley, who is working on the EPA contract study Ijvrsonal communication. February 23, 1976), of 7 cars in which 30-00 min grab samples were taken in 197.7 under varying heat and sunlight conditions, one reading was 1.2 ppm VCM, one 0.4 ppm and the remaining five less than 0.05 ppm (the detection limit). The car with the highest reading was sampled one month after assembly under the following tem perature conditions: ambient SG^C, interior air of car 60C, seat surface 66C. No attempt was made to follow any decrease in off-gassing of RVCM over time. Given the number of individuals exposed to "new car atmospheres" and cars or other motor vehicles generally, some further data on the RVCM content of PVC auto fittings might be useful. Even if risk to consumers from RVCM in PVC sent covers is low, what is the risk of harm to persons working in automobile fac tories? A recent study by Infante et al (10) is espe cially interesting. The data collected by In fante have been interpreted to suggest that VCM may exert a mutagenic effect on sperm cells of PVC production workers, leading to an increase in fetal deaths among pregnancies of workers' wives. Infante's findings are not surprising in light of the demonstration by Dueatman et al. (11) of chromosome aberra tions in PVC production workers and the find ing by Ames (12) that VCM is mutagenic in a Salmonella test system. The sewing of vinyl automobile upholstery and other vinyl fabric automobile fittings is, evidently, in large part woman's work. Even given the multicomponent nature of the PVC in auto fittings, it might be interesting to de termine the incidence of cancer, stillbirths, and birth defects in offspring among women vinyl auto uplioistery workers. Wind happens to PVC on pyrolysis? There seems to be some disagreement as to whether VCM is liberated (hi) or whether the princi pal health threat from burning PVC is caused by evolution of IIC1 (U, 15). Has there been a definitive demonstration that VCM is not |<>lved during pyrolysis of PVC? What about tiepolymcrixation on aging? in sunlight? in heat ? PVC exposure has been linked both to der matitis and Raynaud's syndrome or occupa tional acroosteolysis (10). Dermatitis could be attributable to several of the additives in PVC. or possibly to VCM itself. A catalog of resin components which have caused skin sensitiza tion reactions would be useful. One of the important consumer uses of PVC is in food packaging. Regulations recently pro posed by the United States Food and Drug Ad ministration (FDA) (17) deal with PVC food packaging. Although industry data (IS) have been presented to FDA which indicate migra tion of VCM from PVC as below 50 ppb (the "lowest detectable" level established by the FDA proposal), challenges (19) have been raised to permitting use of PVC food wrap if there is any RVCM capable of migrating. The debate about PVC food wrap points up what may be the salient characteristic of PVC considered as a source of residual VCM: RVCM contained in PVC has now joined the ranks of other carcinogenic substances whose presence in trace amounts.--the amounts limited only by the means of detection--in the US food supply is forbidden by the Delaney Clause, an amend ment to the United States Food, Drug and Cos metic Act. That clause reads in pertinent part: . . no additive shall be deemed to be safe if it is found to induce cancer when ingested by man or animal, or if it is found, after tests which are appropriate for the evaluation of the safety of food additives, to induce cancer in man or animal . . (20). FDA's attempt to set a nonzero tolerance for VCM in food wrap has been challenged as illegal due to conflict with the Delaney Clause (19). It may be that final promulgation of a proposal setting a nonzero tolerance for RVCM in food wrap will be challenged in the courts. Efforts to reduce VCM residual in PVC have come a long way in just over two years. The industry has demonstrated its ability to reduce VCM levels in PVC production plants from hundreds or thousands of ppm to a level close to or at the OSIIA 8-hv TWA of I ppm. Since chemical reactions rarely go to comple tion and are usually reversible, will it ever be possible to produce a PVC resin completely free of residual VCM and incapable of breaking down to release VCM? The stumbling 1 dock for the continued health and growth of the PVC industry may well prove to be not the threat of massive doses of VCM and high potential risk October 1976 111 % s it ' of cancer for the few, bat the threat of lowdoses of VCM and a low but nonzero risk of cancer for the many. The presence of RVCM in PVC represents a potential health hazard for the large number of humans exposed to resin or, more commonly, finished plastic goods. The dusty nature of PVC resin may represent a health hazard for per sons with an occupational exposure to PVC. Where could PVC dust represent a signifi cant hazard? In a polymerization plant, work stations which could be dusty include drying and bagging areas, storage rooms or sibs where PVC resin is held for shipment, mixing areas in compounding and/or fabrication facil ities, and baghouses or cyclones in production or fabrication facilities. If the dusty operations are not completely isolated from the remainder of the production or fabrication facility, dust hazards could be present throughout the plant. How dusty do PVC plants get? Two photo graphs (Figs. 1 and 2) taken in 1975 in a large PVC polymerization facility in the U.S. (21) may lie of interest. Figure 1 gives a general idea of the powdery coating on the equipment in the bagging area; Figure 2 is a picture of L!| floor of the plant: note the depth of the dust, 1 indicated by the footprints. PVC dust concentration data are not readily available; at least, the author had difficulty ob taining such data from labor, government, aca demic, and industry sources. It would be very helpful to those interested in problems of dustcaused disease for industry, labor or govern ment to take measurements of PVC dust in the workplace and make them public. Particle sizes within the respirable range have been noted (W. J. Nicholson. Ml. Sinai School of Medicine, personal communication. February 18, 1976) in a U.S. PVC polymeriza tion plant, not the same plant as the one in which the photographs displayed as Figures 1 and 2 were taken. __- ~ ------- ** Sli r R&S 108139 m fe&i 1 0*4.> i Hp'-rM* 1? vs** V r-- .-`f, ^ .* H *4 ^ w - t }1 C. # ---- * . tar |1 p. li* it: I'lcntF. 1. Bagging area in PVC manufacturing facility. 112 Environmental Health Perspectives MBWW '2?& ,u.. CTW '".' r^-r^r-r.^v-. ' \ e-,ij :mw: ^4 tos sSrs ---N. '**>'" . A-;; Ficunc 2. Floor of PVC manufacturing plant. A number of clinical studies (22-24) have demonstrated pulmonary abnormalities in PVC production and fabrication workers. Abnormal ities have ranged from decreased pulmonary function as measured by FEV to pulmonary rihrosis. Given the data currently available, work is needed to separate the effects on the lung and respiratory system of VCM from those of PVC dust. Experimental studies associate pulmonary fibrosis with exposure of animals to PVC dust. In a recent paper from Italy, Frongia et al. 125) performed a series of studies with a sim ple basic plan-place guinea pigs or rats in cages in the hugging urea of a PVC polymerization plant and observe the effects on the animals' lungs. These animal experiments were inspired by a clinical report of PYC-induced pneumoiimiosis (in'). The Frongia group, after microsou pie examination of tissues of the animals u^hr study, concluded that they had demon^^d a pncumoconiotic reaction brought on \ by PVC dust. Experiments reported as "in progress" as of late 107-1 were designed to de termine whether the pulmonary fibrosis was reversible on cessation of exposure to PVCData on reversibility of pulmonary and respira tory effects of PVC exposure should also be obtained for human populations. Work is needed to determine whether VCM exposure heightens pulmonary response to PVC dust or whether, conversely, PVC dust may convey low levels of VCM or additives to the lungs." Possible enhancement of dust effects by other chemicals in the work atmosphere and/or the additives in the PVC resin should also he investigated. PVC dust could also be swallowed. Volkheimer (27) has found that PVC particles can * According to Milieu- ot al, (2.!) "...If exposure to vinyl chloride and/or PVC is causally related to air flow impairment, we do not know which substance is more pathogenic. The tine dust of the polymer might he mo,, likely to eoneentrate in and damage the small airway.-. This dust, and other small respirable particles, perhaps front tobacco smoko, may also servo as carriers for molecules of a monomer gas to settle in these airwavs." October 1970 _ V.Jt at* V R&S 108141 be "persorbed" from the intestine into the lymph or blood systems. The effect of lr..-:iHy high concentrations of PYG particles carrying minute amounts of potentially Ieachable IIVCM or additives merits investigation, especially as concerns contact with lung or liver tissue. The possibility of PVC dust serving as a skin irritant should be explored. PVC dust could serve as an efficient means for bringing a sen sitizing compound into contact with the skin. The suggestive nature of the clinical and ex perimental data available at this time supports reduction of PVC dust levels in polymerization, comnounding and fabrication facilities. The OSHA standard (28) does not include PVC dust protection or reduction regulations, al though such regulations were recommended bv NIOSH.f Major categories of PVC additives are color ants, fibrous reinforcements (e.g., asbestos), flame retardants, plasticizers (e.g., phthalic acid esters) and stabilizers (e.g.. ovganotin compounds) (28). Based on experimental and/ or clinical data, questions are in order as to the safety of representatives of t ich of these chem ical classes. For instance, Ames (20) has recently re ported that a certain flame retardant compound used in children's sleepwear is highly mutage nic in a Salmonella test system. Compounds ex hibiting mutagenic activity in this bacterial test system are likely to be carcinogens as well. What about the toxicity of flame retardants used in PVC plastics? In September 1072. NIEIIS held a confer ence on phthalic acid esters (30). What is the f To date, neither the US OSHA nor the US EPA has taken any specific steps to reduce PVC dust con sidered as dust. Oust reduction and protection was recommended to the OSHA by NIOSH; EPA in its standard support document (4), states: "With regard to the potential problem of polyvinyl chloride particulate as a possible cause of pneuumoeoniosis, NIOSH is currently involved in experimental studies on the effects of the particulate in animals. The extent of public exposure (as opposed to occupational exposure) to ambient concentrations of the particulate is unknown at this time. Ambient measurements of polyvinyl chloride particulate have not been made by KPA in the vicinity of industrial sources because no technology is currently available for separating poly vinyl chloride particulate from total suspended par ticulate. As data become available from NIOSH and other sources on the health effects of polyvinyl chloride particulate, Ll'A may find that it is necessary to re evaluate the need to propose standards for polyvinyl chloride particulate." current thinking of regulators and researcher? regarding the safety of these chemicals? There is considerable documentation of toxic effects of certain organotin compounds (3^ The biocidal activity of organotin eompmmrai several of which are being used as pesticide? at present, should cause concent about possible effects of organolin plastics additives on human health. The possibility of complex interactions among PVC plastics components and between the components and living systems should be emphasized. Most probably, very little is known about these interactions. NIEIIS has in progress projects designed to identify chemicals which should be studied for possible adverse health effects for humans. Be cause of its wide population exposure due to enormous production volume and broad spec trum of uses and health problems already asso ciated with VCM and PVC dust and certain ad ditives, PVC seems a likely candidate for fur ther investigation. . Given the current state of scientific knowl edge--at least as regards data available for public scrutiny--producers and fabricator's of PVC cannot assure flic public that PVC plastic? are safe for human use. Therefore, interested scientists the work' over, whether working for industry, govern ment, or labor unions, or engaged in research at universities, should make a concerted effort to collect and analyze such data as are available at present on possible risks of harm to human health attributable to PVC. Scientists shook identify research which should be carried out k determine whether or not the family of PVC plastics is safe for general use. and seek the necessary funding to carry out whatever stud ies are needed. REFERENCES 1. Levinson, C. Vinyl Chloride: A Case Study of tk' New Occupational Health Hazard. International Chemical Federation, Geneva, Switzerland, 10T1. p. 15. 2, Rowe. V. K. discussion to Ann. N,Y. Acad. Sci. 2M 317 (lUT,-.). Anon\moils. Tennero PVC resins have VCM dew for a 1 count . . . down to in units per million (a-! vertisemeut 1. Wall Stiret Journal. July 0, 1075, p. t 1. Environmental Protection Agency. Standard Ssr port and Environmental Impact Statement: Emis sion Standard for Vinyl Chloride. EPA--150/2-75000, U.S. Environmental l'intirtion Agency, OflV' of Air and Waste Management. Office of Air Qunlil! Planning and Standards, Kesnauh Tiiangte Pad- North Carolina, October 107.5. 114 Environinenlul Health Perspective? NIOSH Register of VCM-relatcd angiosarcoma cases; this is one of the continuing scries of tabu lations published by the agency. Wagoner, J, lx. Vinyl chloiido. Heaving before the Subcommittee on Environment of the Committee on Pomim-ive, L nited Suites Semite, August 21, 1071, Sv iinl No. 93-110, U.S. Ciovornmeut Printing Office, Washington, D.C. 1!)7I, (a) p. hi; (h) p. GO. Standaid for Exposure to Vinyl Chloride, Occupa tional Safely and Health Administration, Depart ment ol Labor, 39 h'ed, Keg. 35S9U (October 1, 1271). llarnhart, \V. L.. Toney, C. R., and Devlin, J. B. Environmental,'industiial hygiene surveys of vinyl chloride monomer manufactuiing operations and operations where polyvinyl chloride and copolymers of polyvinyl chhnide arc processed. Contract No. CDC-99-7 i-GD, U.S. Department of Health, educa tion and Wclfmc, Public Health Service, Center for Disease Control, National Institute for Occupa tional Safety and Health (August 1075). Feairheller, W.1L, Cheng, J. T., and McCormick, 11. J. Sampling of automobile interiors for vinyl chloride monomer. EFA Contract No. GS-02-1401, Task 1, Cost and Pei formaiuo Report, 1 June 1D7G to 21) June 1975, Envii onmental Protection Agency, Research Tiiangle Park, North Carolina. Infante. P. F., ot al. (lenctic risks of vinyl chloride. Lancet (i) 197G: 743. Ilucntman, A., Hirshcbhorn, K., and 1. J. SelikofT. Vinyl chloride exposure and human chromosome aberrations, Mutation Res. 31: !(!.'! (1975). 12. McCann, J., et al. Detection of carcinogens as mutagens in the .Vd/mniiWhi/microsome test; assay of 20(1 chemicals. Proc. Nat. Acad, Sci. U.S. 72: GRIG (1971), IS. Boettner, E. A., Ball, G. I,., and B. Wreiss. Com bustion products from the incineration of plastics. KPA Grant No. EP-U03SG, Program Klement No, 11)211(1:1, EPA-G7l)/2-7:!-tM!>, 25, 2G (July 1973). 11. Dyer, R. F., and F.seh, V. 11. Polyvinyl chloride toxicity in fires. J. Amor. Med. Assoc. 235: 393 l1970). 1.1. llornblower, M. Plastic fumes insidious. Washingleu Post, December 11, 1*175, p. A8. I'reeei'ilir.gs of Inleruatioual Workshop on Vinyl Chloride, May 1971. Ann. N.Y. Acad. Sci. 2-1G, 1975. 17. Department of Health, education and Welfare, Fund and l)iug Administration: Vinyl Chloride polymers in contact with food, Notice of Proposed Rulemaking, Fed. Register 40: 40529 (September 3, 1975). 18. Heckman, J. Society of the Thistles Industry, Inc.: Submission for the Record in FDA Docket No. 75-N-0190; Vinyl Chloride Polymers in Contact with Food; Notice of Proposed Rulemaking, 40 Fed. Reg. 10529, September 3, 1975 (December 19, 1975). 19. Johnson, A., and Wolfe, S. Submission for the record in proposed FDA regulation Vinyl Chloride l'olvmers in Contact with Food (December 19, 1975). 21 USC S 348(c) (3) (a). Wod.ka, S. Oil, Chemical and Atomic Workers In ternational Union, Citizens-Legislative Depart ment, Washington, D.C. Photographs taken in un identified PVC polymerization plant. Lilis, II., et al. Prevalence of disease among vinyl chloride and polyvinyl chloride workers. Ann. N.Y. Acad. Sci. 246: 22 (1975). 23. Miller, A., et al. Changes in pulmonary function in workers exposed to vinyl chloride and polyvinyl chloride. Ann. N.Y. Acad. Sci. 24G: 42 (1975). 24. Vegmnn, D. comments in discussion to paper of Lange, C. E., et al. Further results in polyvinyl chloride workers. Ann, N.Y. Acad. Sci. 240:20 (1975). l'rongin, N., Spinazzola, A., and A. Bucavelli. Lesioni pulmonari spcrimrntali da inalazione prolungata di polveri di PVC in ambicutc di lavoro (Experimental lung damage from prolonged in halation of airborne PVC dust). Med. I.avor 5: 321 (LD74). Szendc, T?., et al. Pneumoconiosis caused liy tire in halation of PVC dust, Med. Lavor Gl: -133 (1970). Volkheimer, G. Hematogenous dissemination of ingested polyvinyl chlui idc particles, Ann. N.Y, Acad. Sci. 21G: 1G1 (1975). 28. U.S. Department of Labor, Occupational Safety and Health Administration, Standard for Expo sure to Vinyl Chloride. Fed. Register 29: 35890 (October 4, 1974). 29. Blum, A., and Ames, B. Flame retardant additives as possible cancer hazards: chemicals added to chil dren's pajamas may be the wrong solution to the problem of tires. Science, in press. Perspective on PAEs. Environ. Health Perspect. Exp. No, 3, 1973. Piver, W. T. Organotin compounds: Industrial ap plications and biological investigation. Environ. Health Perspect. 4: 01 (1973). 3 October 197G 115