Document zo0rzq1mORoYJO50ODBzbZGK6

- Js. - . . j U^iUTO'njUJ SOUTH CHARLESTON PLANT UNION CARPIDE CORPORATION CHEMICALS AND PLASTICS p. O. BOX 8004, SOUTH CHARLESTON, W. VA. 25303 July 17, 1974 Mr. David R. Bell Office of Standards Development Room 500 Occupational Safety and Health Administration Department of Labor 1726 M Street N. W. Washington, D. C. 20210 Draft Environmental Impact Statement-Vinyl Chloride Dear Mr. Bell: Attached are detailed comments on the Draft Environ mental Impact Statement-Vinyl Chloride to be attached to a general state ment sent you earlier by Mr. J. W. Whittlesey Union Carbide Corporation 270 Park Avenue New York, N. Y. I hope these additional comments will be of value in revising the Draft Statement. Very truly yours, !; . Attac hmem cc: Mr. J. W. Whittlesly Dr. A. B. Steele Dr. N. L. Zutty Mr. M. E. Eisenhour Mr. J. L. Carvajal R. N. Wheeler, Jr. VVC 000005375 DRAFT ENVIRONMENTAL IMPACT STATEMENT Proposed Regulation. Vinyl Chloride COMMENTS Summary Pago Z The second paragraph implies that 13 people in the U. S. died recently of angiosarcoma. The initial death in this series occurred in 1961 and the last two occurred in 1974, a 14 year period. Summary Page 3 The method of analysis as specified permits a variability in absolute vinyl chloride concentration of 0. 3 ppm to 3 ppm. The proposed standard calls for no detectable by this method but the last paragraph states that the proposed standard is to assure that levels do not go above 1 ppm. In addition states that*the employer is required to initiate engineering and work practices deiigned'-to bring the level below 1 ppm. This is all very confusing. Summary Page 4 The last paragraph states that the proposed standard will reduce pollution of the environment external to the immediate work place. This ia a conclusion based on no data. All discussions in regard to control of the work place air have stressed ventilation i.e. remove the vinyl chloride from the work place and blow it into the external air. Summary Page 5 "The proposal is not without adverse consequences. The standard for the most part will likely cause a slight decrease in productivity and a small increase in costs for products made from vinyl chloride." 000005376 VVC Summary Page 5 (Cont'd) This is a conclusion not based on the facts presented in the statement and is contrary to industry statements that the proposed stand ards will cause withdrawal from the business. The carcinogenic potential of vinyl chloride will not initiate a search for substitutes for polyvinyl chloride products are not hazardous to man; therefore, the only incentive to replace them will be economic. This does not fit with the statment that productivity will decrease slightly and there will be a small increase in costs of PVC resins. Page 22 IV Occupational Exposure to Vinyl Chloride Paragraph 2 This paragraph ignores the fact that after the vinyl chloride poly merization step the polymer is exposed to a vinyl chloride stripping or removal step. The final vinyl chloride monomer content of the resin is a function of resin particle size, particle porosity, and the efficiency of the monomer removal operation. The unconverted monomer contained in the resin is a factor in worker exposure only if ventilation at the first processing is poor or if the worker enters a closed vessel containing resin. OSHA is obviously concerned with the migration of VC to the surface of a PVC product since the proposed standard often refers to resin containing detectable quanti ties of vinyl chloride monomer. Page 25 (l) Process Descriptions "Until the late 1950's VC was generally produced from acetylene and hydrogen chloride. " Vinyl chloride was initially produced in the U.S. by caustic hydrolysis of ethylene dichloride. This process was followed by pyrolysis of ethylene dichloride to vinyl chloride and hydrogen chloride. Since hydro gen chloride was a pollution problem, the material was reacted with acetylene to yield vinyl chloride. The statement that vinyl chloride prior to the 1950's was generally produced from acetylene and hydrogen chloride is erroneous. "Acetylene Route . . . The product gases are then purified to vinyl chloride by water and alkaline scrubbing, drying and.finally fractional distillation. M The product gases are fractionally condensed. The liquid conden sate is then fractionally distilled to recover the pure vinyl chloride. The purified vinyl chloride is often caustic scrubbed after distillation. VVC OOOOS377 Acetylene Route (Cont'd) The oxychlorination process from ethylene to ethylene dichloride to vinyl chloride is replacing the "balanced" or acetylene route because of the high cost of acetylene, not because of greater efficiency. 3. Page 28 Process Descriptions The differences noted between PPG and Shell in workers employed per million tons of vinyl chloride capacity is due to failure to secure the same information from both producers. Shell is giving information on all workers involved including maintenance and services whereas PPG has given informa tion on only workers directly involved in production. Page 33 Process Descriptions "Four basic processes polymerization* The bulk process is a dry process requiring no water, suspending agents, or emulsifiers, the other three processes require water, solvents, or other liquids, but they are similar enough that they can be used in the same equipment. " This statement implies that any given suspension, dispersion or solution polymerization plant can operate on any other process. This impli cation is erroneous. Each process uses a specialized plant to produce products for a particular market. Page .33 (1) Process Descriptions In the United States approximately 78% of PVG resins are produced by suspension polymerization, 13% by emulsion polymerization (not solution as printed), 6% by bulk polymerzation and 3% by solution polymerization. Pago 34 Suspension Polymerization Tire PVC slurry is then blended in another vessel with other batches to reduce small variations, and dewatered by a continuous solid bowl centrif ugal (Superdecanter is a trade name) to yield a polymer cake containing about 20% moisture. oooo5373 >/V C Page 34 Emulsion Polymerization "This process is very similar to the suspension process and is used to produce very fine particles. There are two primary differences: (1) Usually two emulsifying agents are soluble in water and one soluble in the monomer, are used to prevent coalescence of the polymer particles, and (2) The polymer is separated from the water by spray drying," This is erroneous. The suspension polymerization process uses mechnaical mixing to suspend monomer particles in water and thereby pro duces large spherical particles. The emulsion process uses one or more surfactants and agitation to convert the monomer and water mixture to a stable emulsion containing very fine particles of monomer which polymerize to very fine particles of resin in a stable latex. The polymer is recovered by spray drying because there is no choice but to use this form of drying. Page 35 Bulk Polymerication "The output of bulk processing plants is said to be more than twice that of good suspension plants of comparable size. M A resin plant is normally sized by its output; thus this statement is in error. The author may have meant that output per fixed investment dollar is twice that of suspension plants. Page 36 Solution Polymerization The author of this section obviously took this information from an ancient patent. The process description is erroneous. Pago 53 V The Proposed Standard Detailed comments on this Proposed Standard are as follows: vve 000005379