Document mB8ma5BKqkwx0GEj0b1xGyxz0

corrected through area monitoring and em ployees can be alerted so as to avoid areas of unacceptable exposure. Personnel monitoring, on the other hand, may possess advantages in terms of assessing the potential exposure of individual employees, but not necessarily actual exposure. However, area monitoring, supple mented by personnel monitoring, can and should serve both purposes provided good recordkeeping practices are adopted. Coordi nation between the recordkeeping activities of personnel and industrial hygiene functions is an essential step if the linking of exposure read ings to individual employees is to be accom plished. The capability for carrying out this linkage step and for correlating exposure to health indices has been greatly enhanced by the availability of modern data processing equip ment and systems. Development of sound animal toxicology, good engineering and industrial hygiene pra tices, and employee education are all funda mental to assuring a safe work environment. Although the efforts required to conduct long term observational health studies are substan tial, concern for the health of our employees will provide the impetus to take this further step to validate occupational health standards. References I. Keenan, R. G.: Problems Associated with Drafting of Criteria Documents. J. Occ. Med. ' v 710 (1973). 2. Ott, M. G.. B. B. Holder, M.D, and H. L. Gordon, M.D.: Respiratory Cancer and Occu pational Exposure to Arsenicals. Arch. Env. Hlth. 29:250 (1974). 3. Mutchler, J. E.: Industrial Hygiene Engineer ing and the Process-Environment Systems. Am. Ind.Hyg.J. 37:233 (1970). new PVC technique announced... The chemical division of B. F. Goodrich re cently revealed development of a new method for removing vinyl chloride monomer from general purpose polyvinylchloride (PVC) resin. This will aid in meeting recent federal standards for worker exposure to vinyl chloride. The new system is based on a continuous stripping process and will be implemented in all 5 Goodrich PVC manufacturing plants by the end of the year. The technology will be made available to other PVC producers under licensing agreements. Cost of introducing the new process into the plants was not revealed, but the conversion will be included in the $42 million earmarked for PVC compliance expenditures over the next two or three years. The new process produces resins with such'low residual VCM level that processors and fabricators who use the resins probably will not need to establish regulated areas under the OSHA worker exposure standards. Also, BFG said the process should aid in reducing VCM emissions from polyvinylchlo ride plants to a level that would be acceptable with regulations being discussed by EPA. The new process uses steam fed into n.e bottom of a stripping column which collects vinyl chloride from the PVC resin as it rises. The columns are simple to operate, will in crease raw material efficiency and process a wide range of resins. Licensing agreements have been signed with several outside PVC manufacturers at the present time. The various anlytical procedu, environmental samples all sut extent that there is no accept: a minor research effort. Many uncertainties are related to ar Free silica anal a critical literal PAUL L. ANDERSON Kaiser Aluminum Chemical Corpo technology, P.O. Box 870, Pleasa< Introduction This communication reports thi literature survey dealing with tl analysis of free crystalline silicr relates to the industrial hygiene silicosis. A short review of the silic; erals is followed by critical revi various methods: solution chen diffraction, differential thermal troscopic, and some miscellanei A review of the quartz high soh phous surface layer problem is While this review is not ex sufficient scope to point out ind Icms with the various analytical also shows that the basic under: silica mineral family is so poor i crystalline silica analyses with a of accuracy is improbable. Evei of free crystalline silica is in qui The silica family'^ The simple chemical comblnati' and oxygen with the addition ol Bachelor and Science degree mineralogy an istry from Bri| University and of Utah,1958 respectively. G the State of A; years and for California for 4 Geochemist ar -^Searcher for minum & Chet pcration for el October. 19;S *-T,encan Industrial Hygiene Association Jot