American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California. Fairfax, VA: American Industrial Hygiene Association, 2005 May; :73
A retrospective chemical exposure assessment of workers at the Portsmouth Naval Shipyard (PNS) has been completed as part of a multi-site case-control study of leukemia mortality and external radiation. A method was developed to assign exposure scores based on year, job title, and shop utilizing an exposure weighting factor: 1, 0.5, 0.1, 0.01, and 0. The weighting factor was assigned for each year, job title, and shop based upon knowledge of work activities, chemical monitoring and inventory data, engineering controls, and personal protective equipment. A work history database was created from shipyard employment records. The 363 original job titles were collapsed into 88 job titles. The 177 PNS subjects were employed at various times between 1917 and 1998, and 80 (45.2%) were classified as solvent exposed for at least one year at PNS. An exposure score was calculated for each year, job title, and shop combination for both benzene and carbon tetrachloride by multiplying the exposure level weighting factor (WF) by the duration (D) in hours per day, and the frequency (F) in days per year, ?(WF*D*F)job/shop. The average annual exposure score (AAES) for years with a minimum of 10 subjects peaked in 1945 with a combined solvent score of 233. The highest AAES for benzene and carbon tetrachloride occurred in 1945 and 1940 respectively. Cumulative benzene scores were greatest for painters, and cumulative carbon tetrachloride scores were greatest for electricians. The most frequent job titles were pipefitter, electrician, and laborer. The exposure scores, normalized to current occupational limits, will be used to compare the study subjects across the multi-site study. Exposure scores are not intended to directly represent actual exposures; they are used to categorically rank the study subjects across the multiple sites.
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California