Document MLxdvoD5nYE1817N6JeXEqRL

PROGRESS IN VINYL CHLORIDE CONTAINMENT A Report By The B.F.Goodrich Company IlSiSy December 4, 1975 N 2 5 BACKGROUND he B.F.Goodrich Company was Tfaced with a number of serious and difficult decisions when we discovered, in January, 1974, that three of our employees who had worked for many years in our Louisville, Ky., poly vinyl chloride plant had died from a rare form of liver cancer, angiosarcoma. Subsequently, additional cases were identified and reported among poly vinyl chloride production workers in plants of various companies in the United States, Canada, Europe and Japan. In all these plants polyvinyl chloride (PVC), a solid resinous polymer which is the base material for the vinyl plastic industry, is produced from vinyl chlo ride (VC), a reactive gaseous monomer. Goodrich has produced PVC since 1937. Prior to 1974, its programs to provide a safe work environment in keeping with known scientific data already had re duced the concentration of VC gas ex posure to an average of less than 100 parts per million (ppm). The angio sarcoma discovery, however, added a new dimension to the problem of VC confinement. The Company took immediate action. We informed our employees, appro priate government officials, customers, others in industry and the public of all pertinent facts. We searched medical records and medical examination re ports of all employees who could have been exposed to vinyl chloride to as certain the existence of physical abnor malities. We began immediately to re examine our manufacturing operations -- to explore, in the light of the tech nology that was then available or could be developed in the short term, all pos zaezisiz sible ways to confine VC inside equip ment and prevent its escape. With faith in our technological ability and with great concern for worker safety, the Company made the decision to con <.aL*. tinue both with PVC production and Mth plans for expansion at the Louisville *- rl Plant. could have been interpreted as in dicating permissible exposure of 1.0 ppm or 0.5 ppm, or as requiring no exposure whatsoever. 2. The four types of respiratory equip ment listed as acceptable for pro tection against vinyl chloride were all to be self-contained. Such equip ment would have been totally im practical because weight and bulk of tanks, hoses, etc. would have severely limited worker mobility. Further, the limited air supply in self-con tained equipment, enough for only 30 minutes, would have required re supply so frequently that these sys tems also would have been imprac tical. 3. Protective clothing called for in the proposed standard would have placed additional unacceptable re straints on worker mobility. This clothing also would have exposed the wearer to severe heat stress, particu larly when worn in confined areas and where the work required sub stantial physical effort. Within established Federal procedures, and in open hearings and in open records, Goodrich and industry experts provided extensive technical information on con trol of industrial gases under pressure and work practices, and realistic information on the possibilities for engineering con trols. The permanent OSHA standard is sued on October 5. 1974, is stringent, but is more realistic and much less ambigu ous, and sets forth detailed specific para meters for industry action. It requires that worker exposures be no more than 1 ppm on a time-weighted average for 8 hours, and no more than 5 ppm for any 15-minute period. Under the standard, respira tors are made available to all workers. Until April 1, 1976, their use is optional up to 25 ppm, but is required at higher levels. After April 1, 1976, respirators are mandatory for exposures above the 1- and 5-ppm levels. >50512085 Asone of the first steps in its intensified program, Goodrich quickly developed monitoring systems to measure ambient VC levels in work atmospheres on a con tinuing basis. These systems have been continuously improved and now are very accurate and reliable. Portable monitoring devices were re quired to enable engineers to locate quickly leaks or sources of vinyl chloride in plants. Since VC gas is continuously under pressure in the PVC manufacturing operations, even the smallest apertures in the hundreds of valves, flanges or similar equipment in plants can release the gas into the work atmosphere. Another of the first tasks was to locate all these sources and make them as leakproof as possible. In many cases, this re quired the development or special pro curement of new, more highly engineered pumps, flanges and gasketing materials, and also extensive re-engineering of pip ing systems to reduce the number of pos sible leak sources. Still another step was the installation of new ventilation systems in buildings in which PVC operations are conducted. This substantially reduced VC in work areas where it was most likely to concen trate. Automatic alarm systems were in stalled to indicate if VC concentrations should reach levels requiring respirators, or evacuation of personnel until an emer gency situation can be corrected. New Reactor Cleaning Technology PVC manufacture from VC in existing plants is a batch..operation in which re actors are charged, eipptied and recharged repeatedly, and in which solid material normally deposits or builds up on reactor interiors during each batch reaction. Re actors are large, sealed pressure vessels in which vinyl chloride gas is converted (polymerized) into the solid polyvinyl chloride resin, or plastic. Reactor cleaning to remove this build-up between charges has, in the past, been a principal source of worker exposure to VC, because unre- '21S12006 problem with VC exposure from finished foods. However, a question has been raised about the possible migration of vinyl chloride into food from packaging materials made of PVC compounds. In September, 1975, the Food and Drug Administration proposed new regulations affecting the use of PVC in a number of food-contact applications. Under these proposals, PVC resins and compounds fabricated into bottles, blister packs, boxes, and other semi-rigid and rigid packaging that comes in contact with food would no longer have FDA approval. The regulation would continue to permit PVC use in pliable film-type wraps, gas kets. cap liners, pipe, tubing and packag ing coatings. It should be noted that the FDA action to date is only a proposal, not a final reg ulation, and comments on the proposal are being received for consideration. Two comments are worth special mention in this regard. First, as we announced last May, our Company is producing new PVC bottle compounds containing significantly less than one part per million (ppm) of VC. The Company has been unable to detect vinyl chloride, by analytical methods sen sitive to 50 parts per billion (ppb), in foodsimulating solvents when the package is fabricated from compounds containing 1 ppm or less of residual vinyl chloride. Secondly, the FDA proposal leaves the door open for suppliers or users of PVC packaging materials to submit food addi tive petitions and secure FDA approval if their supporting data demonstrates there would be no reasonable expectation that vinyl chloride would become a component of the packaged food. Should the present proposed regulations become final, Good rich believes that packaging materials fabricated from its new PVC compounds will meet this criterion for approval. New Stripping Columns Developed A major factor in our Company's abil ity to produce PVC compounds that are extremely low in vinyl chloride content has been the development of a new im proved continuous method of stripping vinyl chloride from PVC resin during its manufacture, as announced by the Com pany on August 26. In the new process, resin made in slurry form from VC in a group of reactors is continuously fed into the top of an especially designed stripping column countercurrent to steam fed at the bottom of the column. As the column is operated under controlled conditions, the steam rises to the top, picking up al most all the VC in the resin flowing down ward. The VC is collected and recovered for reprocessing, while the stripped slurry is removed at the bottom. Virtually all the remaining VC is removed in drying of the slurry. Goodrich is now installing the new stripping columns in all of its PVC plants and, as a result, we are producing general purpose resins with an ultra-low residual VC monomer content -- in ranges below 1 ppm. It is believed that processors and fabricators using these resins will not have to establish regulated areas in their plants under the OSHA regulations. Regulated areas are those in which the time-weighted average in the work area is greater than one-half part per million (0.5 ppm). Plant Environment The Goodrich stripping technology is also a key to progress in the third category of reduction of VC losses, that is, escape to the environment. Since the stripping operation continuously recovers and re cycles all but traces of the VC present in the PVC resin as it comes from the reac tors, there is a substantial reduction in the amount of VC which could be discharged to the environment with the air from the dryer or with effluent from other down stream operations. In other respects, progress in reduction of VC in the work place has been achieved, while avoiding forcing the VC out of the plant into the surrounding environment. Goodrich environmental engineers at each plant, as well as the corporate envi ronmental staff, have carefully analyzed msm&oin-plant control measures for their effect which the Company has developed. With the use of very large reactors, the number of valves, pumps, flanges and other for mer leak sources has been substantially reduced. New stripping columns, reactor cleaning systems and many other new developments are being installed. Good rich engineers believe that this new facil ity will be as good as or better than any other PVC plant in the United States in prevention of employee exposure or escape of VC into the environment, or residual VC in product. We intend to continue our efforts to re duce VC exposure resulting from all our operations and products, and to continue our research and development efforts to refine our techniques and develop new ones. We face the possibility that, because of the long latency period, we will see other cases of angiosarcoma resulting from heavy exposure in the past. But we now feel sure that the chances are extremely remote of this disease re sulting from VC exposure in our current operations. The B.F.Goodrich Company December 4,1975 1512013