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IARC MONOGRAPHS
ON THE
EVALUATION OF THE CARCINOGENIC RISK OF CHEMICALS TO HUMANS
Some Monomers, Plastics and Synthetic Elastomers, and Acrolein
VOLUME 19
This publication represents the views and expert opinions of an IARC Working Group on the
Evaluation of the Carcinogenic Risk of Chemicals to Humans which met in Lyon. 7-13 February 1978
Gift of American Public Health Association February 1979
INTERNATIONAL AGENCY FOR RESEARCH ON CANCER j
O .O
CONTENTS
LIST OF PARTICIPANTS ............................................................................................................ 7
NOTE TO THE READER................................................................................................................. U
PREAMBLE........................................................................................................................................ BACXCROUND ................................................................................... OBJECTIVE AND SCOPE ............................................................................................... SELECTION OF CHEMICALSTOR MONOGRAPHS ............................................................ WORKING PROCEDURES ..................................................................................................... DATA FOR EVALUATIONS ................ THE WORKING CROUP ........................................................................................................ GENERAL PRINCIPLES FOR EVALUATING THE CARCINOGENIC RISK OF CHEMICALS .......................................... .<........................................................... EXPLANATORY NOTES ON THE MONOGRAPHCONTENTS ..............................................
13 13 13 I4* 1* 13 13
16 H
GENERAL REMARKS OK THE SUBSTANCES CONSIDERED ..................................................... 35
THE MONOGRAPHS
Acrylic acid, methyl acrylata, ethyl acrylate and polyacrylic acid ............................................ ....................................................
Acrylonitrile, acrylic and aodacrylic fibres, and acrylonitrile-butadiene-styrene and styreneacrylonitrila copolymers ................................................................................
Caprolactam and nylon 6 ........................................................................................
Chloroprane and polychloroprane .......................................................................
Ethylene and polyethylene .................................................................................... Methyl methacrylate and polymethyl methacrylate ....................................
Propylene and polypropylene ........................ .......................................................
Styrene, polystyrene and styrene-butadiene copolymers ....................... Styrene oxide..............................................................................................................
Tetraflueroethylene and polycetrafluoroethylane ....................................
2,4- and 2,6-Toluene diisocyanates, 1,5-naphthalene diisocyanate, 6,4,-methylenediphenyl diisocyanate, polymethylene polyphenyl isocyanate and flexible and rigid polyurethane foams ..................
Vinyl acetate, polyvinyl acetate and polyvinyl alcohol .................... Vinyl bromide ...............................................................................................................
Vinyl chloride, polyvinyl chloride and vinyl chloride-vinyl acetate copolymers ........................................ ....................................................
47
73 * 115 131 157 187 213 231 275 285
303 341 367
377
22081002
BFG18657
Vinylidene chloride and vinylidene chloride-vinyl chloride copolymers ............ ......................................................................................
A'-Vinyl-2-pyrrolidone end polyvinyl pyrrolidone..................... Acrolein ..............................................................................................................
SUPPLEMENTARY COBRIGENDA TO VOLUMES 1-18
CUMULATIVE INDEX
439 461 479
493
497
IAR'
Members1
J. Autian, D. of Dent: for the America
L. Sibling, 1 Boxschkc
V.J. Feron, C Utrechts
L. Fiehbein, National United
R. Grieseoer, and Prev Marylane
T. Matsushiaf of Medic Japan
R. Owen, Med: Great Ri
G. Farssiani, lo Stud:
M. Roberfroic Ecole dc Bromatol
The following compounds were considered but no monograph was prepared because of lack of carcinogenicity data: adipic acid, hexamethylenediamine and nylon 6/6; diseehylterephchalate, terephchalic acid and polyethylene terephthalate; isoprene and polyisoprene; methaerylic acid; vinylidene fluoride and polyvinylldene fluoride.
BFG18658
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378
I ARC MONOGRAPHS VOLUME 19
(e) Refractlve index
20 1.3700
(f) Spectrosocpy data: Infra-red, nuclear magnetic resonance and
mass spectral data have been tabulated (Grasselli & Ritchey, 1975).
(&) Solubility: Slightly soluble in water (0.11 g/100 g at 25C)
(Hardie, 1964); soluble in ethanol; very soluble in ether, carbon tetrachloride and benzene
<h) Volatility. Vapour pressure is 2530 mm at 20C (Hardie, 1964)
(i) Stability: Flash-point, -78C (closed cup) (Hardie, 1964);
polymerizes in light or in the presence of a catalyst (Hindholz, 1976); on combustion it degrades to hydrogen chloride, carbon monoxide, carbon dioxide and traces of phosgene (O'Mara ct al.t 1971)
Cl) Reactivity: On treatment with strong alkalis at high tempera
tures it loses hydrogen chloride (Miller, 1969).
formerly the most hilogenation of e in the US and Jap ethylene is react, dichloride, which hydrogen chloride
Vinyl chlori. years (US Tariff production of 258 US imports have b. 1976 (US Departme 150 million kg to Canada (8), Colon:
Total wester n the following . epublic of Germar 690). The Nether
In Japan, cot In 1976, eighteen chloride; 115 mil
(k) Conversion factor: 1 ppm in air = 2.6 mg/n3
(b) Use
1.4 Technical products and impurities
Vinyl chloride is generally supplied as a liquid under pressure. Usually no inhibitor is added when it is to be shipped within the US. A typical analysis of a conercial US grade is as follows: water, 50 n-jy(ppm); nonvolatile residue, 5 mg/kg (ppm); acetaldehyde, <1 mg/kg (pps);' acetylene, <1 mg/kg (ppm); iron, 0.1 mg/kg (ppm); hydrogen chloride, <0.1 mg/kg (ppm); and hydrogen peroxide, 0.01 mg/kg (ppm).
In Japan, commercial vinyl chloride ne'ets the following specificatio-** purity, 99.93 ain; water, 200 mg/kg (ppm) max; hydrogen chloride, 1 ng/l (ppm) max; iron, 1 mg/kg (ppm) max; and evaporation residue, 50 mg/k (ppm) max. Chlorinated hydrocarbons may be present as impurities.
2. Production, Use, Occurrence and Analysis
2.1 Production and use
About 96% of was for the produc The remainder was duction of methyl In the production vinylidene chloric
The largest t plastic piping anc in consumer goods, for detailed descr chloride-vinyl act
Hardie (1964: perant, as an ext: production of chic rhonamides); hove ^eing used for ch
(a) Production
The first synthesis of vinyl chloride appears to have been made in
1835 (Regnault, 1835). Addition of hydrogen chloride to acetylene,
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Limited cuan: propellant, but i: iVS Environmental
VINYL CHLORIDE AND POLYMERS
379
formerly Che most important route of synthesis, has been displaced by the
Iglogenation of ethylene; over 95" of the vinyl chloride monomer produced nd In the US and Japan in 1976 was made from ethylene. In this process,
ethylene is reacted with hydrogen chloride and oxygen to give ethylene
bichloride, which is subsequently cracked to produce vinyl chloride and hydrogen chloride.
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Vinyl chloride has been produced commercially in the US for over fifty years (US Tariff Commission, 1928). In 1976, nine companies reported che production of 2580 million kg (US International Trade Commission, 1977). CS imports have been negligible; exports amounted to 291 million kg in 1976 (US Department of Commerce, 1977), and in 1977, exports were about 130 million kg to the following countries (Z of total): Brazil (28), Canada (8), Colombia (11), Mexico (14), Norway (12) and Yugoslavia (14).
Total western European production in 1976 amounted to 3925 million kg, In the following countries (millions of kg); Belgium (490), the Federal Republic of Germany (990), Finland (25), France (620), Greece (25), Italy (690), The Netherlands (340), Spain (190), Sweden (95), Switzerland (30) end the UK (430). Exports from western Europe in that year were 44 million
kS-
In Japan, commercial production of vinyl chloride began prior to 1946. In 1976, eighteen companies produced a total of 1281 million kg vinyl chloride; 115 million kg were exported.
(b) Use
Rg/kg "'P) I
9 About 96Z of the 2274 million kg vinyl chloride used in the US in 1976 4 ms for the production of vinyl chloride hoaopolyaer and copolymer resins, b The remainder vas used (essentially by one company internally) in the proy duction of methyl chloroform and as a comonomer with vinvlidene chloride < in the production of resins. For a detailed description of the uses of I vinvlidene chloride-vinyl chloride copolymers, see p. 450.
`tions; mg/kg S
t TIiu largest use for polyvinyl chloride resinr. is in the production of i plastic piping and conduit. Other important uses are in floor coverings,
is consumer goods, in electrical applications and in transport applications, * for detailed descriptions of the uses of polyvinyl chloride and vinyl
chloride-vinyl acetate copolymers, see pp. 406 and 414.
Kardie (1964) reported that vinyl chloride has been used as a refri: ferine, as an extraction solvent for heat-sensitive materials and in the
production of chloroecetaldehyde (an intermediate in the synthesis of sulphonasides); however no evidence was found that vinyl chloride is presently j being used for these purposes.
Limited quantities of vinyl chloride were used in the US as an aerosol propellant, but in 1974 it was banned from use in pesticide aerosol products
(US Environmental Protection Agency, 1974a), in sclf-prcssurizcd household
380
IARC MONOGRAPHS VOLUME 19
containers, and as an ingredient of drug and cossetic products (US Consumer Product Safety Comaission, 1974a,b).
Vinyl chloride was used in western Europe in 1977 in the production of polyvinyl chloride (95Z) and for other uses, including the production of nethyl chloroform (52).
In Japan in 1976, vinyl chloride was used in the production of poly vinyl chloride (92-94Z) and for other uses, such as in copolymers (6-8Z).
The US Occupational Safety and Health Administration's health standards for exposure to air contaminants require that an employees's exposure to vinyl chloride'not exceed an eight-hour time-weighted average of 2.6 mg/m3 (1 ppm) in the workplace air in any eight-hour work shift of a forty-hour work week. During any work shift an employee's exposure may not exceed a ceiling concentration limit of 13 mg/m3 (5 ppm), averaged over any period of 15 minutes or less (US Occupational Safety and Health Admini stration, 1974).
The work environment hygiene standards for exposure to vinyl chloride in various countries, in terms of time-weighted averages (8-hr) and ceiling concentrations (10- or 15-min), were as follows in 1977: Canada, 10 ppm (8-hr) and 25 ppm (15-min); Finland, 5 ppm (8-hr) and 10 ppm (10mln); Italy, 50 ppm (8-hr), although this is expected to change to 25 pp(8-hr); Japan, expected to be 10 ppm; The Netherlands, 10 ppm (8-hr); Norway, 1 ppm (8-hr) and 5 ppm (15-win); Sweden, 1 ppm (8-hr) and 5 ppm (15-min); USSR, 12 ppm (Bertram, 1977). In France, the standards were reported to be 5 ppm for 1 week, with a celling concentration of 15 ppn, in already existing factories, and 1 ppm and 5 ppn, respectively, for new factories; in Spain, no limits; in Denmark, 1 ppm (8-hr); in Belgium, 5 ppm (1 week), ceiling 15 ppm; in the Federal Republic of Germany, the same as for France in existing factories, and 2 ppm (1 year) and ceiling 15 ppm (1-hr) for new factories; in the UK, 10 ppm (S-hr), ceiling 30 ppm max; and in Switzerland, 10 ppm (1 week, S-hr dav for 5 days) (Thomas, 1977).
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In August 1977, the proposed European value was 3 ppm over one year for existing and future plants, with an 'alarm-value' of 13 ppm (Commission of the European Communities, 1977a).
The US Environmental Protection Agency has proposed new rules to reduce the national emission standard for vinyl chloride from 10 ppm to 5 ppm in order to reduce vinyl chloride emissions by one-half within 3 years of the actual rulemaking. This would result in hourly emissions (based on new average-sized plants) of 5.1 kg from an ethylene dichlorldtvinyl chloride plant (instead of 10.3 kg); 9 kg from a dispersion process polyvinyl chloride plant (instead of 17.5 kg); and 13.5 kg from a sus pension process polyvinyl chloride resin plant (instead of 16 kg) (US Environmental Protection Agency, 1977).
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In the Feder.is limited to 3 k; 0.3 mg/m3 (99Z co:
The Coimaissic 1 mg/kg (1 ppm) a; packaging and 0.0(Commission of the level of 0.05 mg/i Republic of Cermar (Thomas, 1977).
2.2 Occurrence
Vinyl chloric
The occurrem. and polyvinyl chli (US Environmental
(a) Occupatl
The air concc prior to ventilate scraping procedure hands during scrap Between 1950 and 1 found in one facte Air concentrations chloride-producing 100-800 mg/m3 (40(Filatova & Ci onsb ci al 1969); ar. 1976). In a Russi (Bol'shakov, 196?) 0.35 ppm) (Murdoci. mated that ?0 000 chloride in canu:_
On a time--wei mer to which coagu (50-250 ppm) (Bare the US National Ir. chloride plants it vinyl chloride ran Barnhart c: i. (1 mg/m3 (0.01-84.77 ride plants in the
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VINYL CHLORIDE AND POLYMERS
381
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In the Federal Republic of Germany, Che emission In the environment is limited to 3 kg/hr/source or ISO mg/m9/source, with a ground level of 0.3 mg/m9 (992 confidence) In inhabited areas (Thomas, 1977).
The Commission of the European Communities has adopted a level of 1 eg/kg (1 ppm) as the amount of vinyl chloride which can be present in packaging and 0.01 mg/kg (ppm) in foodstuffs packed in polyvinyl chloride (CosBission of the European Communities, 1977b, 1978). A maximum migration level of 0.05 mg/kg has been adopted in Belgium, Denmark, the Federal Republic of Germany, France, Italy, The Netherlands, Spain and Sweden (Thomas, 1977).
2.2 Occurrence Vinyl chloride Is not known to occur as a natural product.
The occurrence of vinyl chloride in ambient air near vinyl chloride and polyvinyl chloride plants, in water, and in food has been reviewed (US Environmental Protection Agency, 1975a,b).
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(a) Occupational exposure
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The air concentration of vinyl chloride in a polymerization reactor prior to ventilation is of the order of 7800 mg/m9 (3000 ppm); during the scraping procedure, 130-260 mg/m9 (50-100 ppm); and that close to the hands during scraping, 1560-2600 sg/m9 (600-1000 ppm) (Cook et al., 1971). Iccween 1950 and 1959, concentrations up to 10.4 g/m9 (4000 ppm) were found in one factory near the polymerization reactors (Ott et al., 1975). Air concentrations of vinyl chloride in working places in polyvinyl chloride-producing factories have been reported variously to range from 100-800 mg/m1 (40-312 ppm), with peaks up to 87.3 g/m9 (33 500 ppm) (Filatova & Gronsberg, 1957); from 112-556 ng/m9 (43-214 ppm) (Anghelescu it al., 1969); and >195 mg/m9 (>75 ppm) in a Yugoslav plant (Orusev et al., 1976). In a Russian synthetic leather plant, <113.6 mg/m9 (44 ppm) (Bol'shakov, 1969) and in three UK cable factories, 0.4-0.9 mg/m9 (0.150.35 ppm) (Murdoch & Hammond, 1977) were detected. In 1974, it was estiosted that 20 000 US workers, past and present?, had been exposed to vinyl chloride in manufacturing plants (Heath ct a.'., 1975).
On a time-veighted average, the concentration of vinyl chloride monoocr to which coagulator operators are exposed ranges from 130-650 mg/m9 (50-250 ppm) (Baretta et al., 1969). However, in a acre recent survey for the US National Institute for Occupational Safety and Health of three vinyl chloride plants it was reported that the time-weighted average exposure to vinyl chloride ranged from 0.2-70 mg/m9 (0.07-27 ppr.) (Milby, 1977). Barnhart ct al. (1975) found <0.03-15 mg/m9 (<0.01-5.89 ppm), 0.03-220 cg/a3 (0.01-84.77 ppm) and 0.05-57 mg/m' (0.02-21.8 ppm) in 3 vinyl chlo ride plants in the US.
22081007
BFG18662
382 IARC MONOGRAPHS VOLUME 19
In 1974, ic was reported that polyvinyl chloride leaving certain manufacturing plants may have contained 200-400 mg/kg (ppm) vinyl chloride monomer; on delivery to the customer, this level was about 250 mg/kg (ppc)and after processing, levels of 0.5-20 ng/kg (ppm) were reached, depending on the method of fabrication (Anon., 1974). Wilkinson ci al. (1964) found 100 mg/kg (ppm) residual vinyl chloride monomer in polyvinyl chloride dis persions. However, new processing methods leave as little as 1-2 mg/kg (ppm) residual vinyl chloride in vinyl chloride resins (US Food and Drug Administration, 1975). Residual vinyl chloride in cossaercial food grade resins has been reduced by processing and stripping techniques to 115 ug/kg (ppb) for resin, less than 0.048 ug/kg (ppb) for compound and less than 0.043 ug/kg (ppb) for sheet polyvinyl chloride (Saggese ci al., 1976). Industrial grade polyvinyl chloride-coated films used for food packaging were found to contain 5-71 Ug/kg (ppb) of monomer (Gilbert et al., 1975) and plastic bottles up to 7.9 mg/kg (ppm) (Breder ci al., 1975).
(b) Air
It has been estimated that prior to 1975 vinyl chloride emissions from US polyvinyl chloride plants amounted to 110 million Ug/vear (US Environmental Protection Agency, 1975b) and that the average concentration of vinyl chloride in air around these plants was 44 ug/m3 (17 ppb) (US Environmental Protection Agency,. 1976). Vinyl chloride has been determined in the air in the Houston, Texas, area (where an estimated 40Z of the US production capacity is locsted) in concentrations of 8 Ug/m -3.2 mg/m1 (3.1-1250 ppb) (Gordon 6 Meeks, 1977) and in the ambient air near two vinyl chloride plants in the Long Beach, California, area in concentrations of 0.26-8.8 mg/m3 (0.1-3.4 ppm) (National Field Investigations Center, 1974). It has also been detected in the air in Delaware City, Delaware, in maxiauc concentrations of 3.9 mg/m3 (1.5 ppm) with a mean of 2 mg/m3 (0.8 ppm) (Lillian ei al., 1975).
(c) Water
Vinyl chloride has been detected in effluent discharged by chemical and latex manufacturing plants and in raw water in the US (Shackelford & Keith, 1976). The highest concentration of vinvl chloride detected in finished drinking-water in the US was 10.0 ug/1*(Safe Drinking Water Committee, 1977; US Environmental Protection Agency, 1975a).
In 1974, ic was estimated that about 12.3 kg/day vinyl chloride were discharged in the waste-water effluent from 2 vinyl chloride plants in the Long Beach, California, area (National Field Investigations Center, 1974).
(d) Food
In May 1973, a branch of the US Treasury Department banned the use of polyvinyl chloride for the packaging of alcoholic beverages (Anon., 1973a), as a result of studies reported by the US Food and Drug Administration indi cating that up to 20 mg/kg (ppm) vinyl chloride monomer were present in
| 3
alcoholic beverag chloride has been ng/kg (ppm) (Will levels of up to 9
It had been (ppm) (Roesli ei In butter and mar et al., 1975), wh chloride contains
(e) Other
Vinyl chlorli concentrations of another study (Go 16 new or used au:
Vinyl chlorii and little cigars. marijuana clgarect
2.3 Analysis
A comprehens: methods of samplir sphere, ambient ai is available (Egar vinyl chloride ha\ 1975b). A review water, and water p
A gas chromat National Institute chloride in the vc
5-litre air sample
1977).
A gas chromat mission of the Eur foodstuffs and in into contact with
An official e of Germany for det It is based on cre by gas chromatogrc Cion and has a lir Kormen Ausschuss,
VINYL CHLORIDE AND POLYMERS
383
alcoholic beverages packaged in this material (Anon., 1973b). Vinyl chloride has been found in a variety of alcoholic drinks at levels of 0>2.1 og/kg (ppm) (Williams, 1976a,b; Williams & Miles, 1975) and in vinegars at levels of up to 9.4 og/kg (ppm) (Williams & Miles, 1975).
It has been found in edible oils, in concentrations of 0.05*14.8 mg/kg (ppm) (Roesli ei-aZ., 1975; Williams, 1976a; Williams 6 Miles, 1975), and in butter and margarine, in concentrations of 0.05 mg/kg (ppm) (Fuchs et al., 1975), when these products were packaged and stored in polyvinyl chloride containers.
(e) Other
Vinyl chloride has been found in 2/7 new automobile interiors in concentrations of 1-3 mg/m1 (0.4-1.2 ppm) (Hedley et si., 1976). In another study (Going, 1976), no concentrations above 10 ppb were found in 16 new or used automobiles or in 4 new or old mobile homes.
Vinyl chloride has been detected in domestic and foreign cigarettes and little cigars, in concentrations of 5.6-27 ng/cigarette, and in a marijuana cigarette at a level of 5.4 ng/cigarette (Hoffmann et al., 1976).
2.3 Analysis
A comprehensive critical review, containing over 100 references, of methods of sampling and analysis of vinyl chloride in the workplace atmo sphere, ambient air, water, food, cigarette smoke and polyvinyl chloride is available (Egan et al., 1979). Methods of collection and analysis of vinyl chloride have also been reviewed (US Environmental Protection Agency, 1975b). A review of methods used to determine vinyl chloride in air, water, and water piping is available (Laramy, 1977).
A gas chromatographic method of analysis has been accepted by the US National Institute for Occupational Safety and Health for determining vinyl chloride in the workplace atmosphere, in the range of 0.008-5.2 mg/nr in a 5-litre air sample (National Institute for Occupational Safety and Health, 1977).
A gas chromatographic analytical method has been proposed by the Com mission of the European Communities for determining vinyl chloride in foodstuffs and in vinyl chloride polymers and. copolymers intended to come into contact with food (Commission of the European Communities, 1977b).
An official analytical method has been drafted in the Federal Republic of Germany for determining residual vinyl chloride in polyvinyl chloride. It is based on treatment of the polymer with .7,.7-dimethylacetanide, followed by gss chromatographic analysis of the solution with flame-ionization detec tion and has a limit of detection of 0.5 ng/kc (ppn) (Deutsche Industrie Normen Ausschuss, 1977).
22081009