PT  - JOURNAL ARTICLE
AU  - M J van Tongeren
AU  - R D Barker
AU  - K Gardiner
AU  - J M Harris
AU  - K M Venables
AU  - J M Harrington
AU  - A J Newman Taylor
TI  - Retrospective exposure assessment for a cohort study into respiratory effects of acid anhydrides.
AID  - 10.1136/oem.55.10.692
DP  - 1998 Oct 01
TA  - Occupational and Environmental Medicine
PG  - 692--696
VI  - 55
IP  - 10
4099  - http://oem.bmj.com/content/55/10/692.short
4100  - http://oem.bmj.com/content/55/10/692.full
SO  - Occup Environ Med1998 Oct 01; 55
AB  - OBJECTIVES: To estimate past exposure to phthalic (PA), trimellitic (TMA) and maleic anhydride (MA) in three alkyd resin and one cushioned flooring factory to estimate exposure-response relations in a retrospective cohort study. METHODS: Personal exposure measurements were carried out in 1992 and quantitative and qualitative information on past exposure and production processes were collected. Job titles were ranked by decreasing exposure and amalgamated into job categories and exposure groups. Multiplication factors for back calculating past exposure levels were estimated with past exposure data, or if no such data were available these factors were estimated by a panel of occupational hygienists. Exposure levels were back calculated starting with the exposure levels in 1992. RESULTS: High exposures to PA were estimated to have occurred among workers operating the PA melting pots in factory 1 (estimated exposure in 1960-9 was 2480 micrograms.m-3). Highest concentrations of TMA were estimated to have occurred among the ink mixers in factory 2 from 1979 to 1986 (554 micrograms.m-3). Exposure in most other job titles was thought to be fairly constant over time for PA, TMA, and MA. CONCLUSIONS: Exposure to acid anhydride at these factories has fallen during the period covered by the study. However, it is estimated that in only one job in factory 2 did past exposure to acid anhydride exceed the current occupational exposure standard. Accuracy of the estimated exposure is limited by a paucity of reliable past exposure data.