Biomedical surveillance of workers exposed to 4,4'-methylene-bis-(2-chloroaniline) (MBOCA) in Perth, Western Australia.

From 1984, a biomedical surveillance programme assessed the occupational exposure to 4, 4'-methylene-bis-(2-chloroaniline) (MBOCA) in seven factories which manufactured polyurethane polymers. Urinary MBOCA concentrations were used to assess absorption of MBOCA which is a scheduled carcinogen under the Poisons Act in Western Australia. The relevance and limitations of urinary MBOCA as a biological indicator of exposure to MBOCA, the use of spot urines based on creatinine concentrations in preference to 24 hour urine MBOCA estimations and urinary cytology are discussed. Preventive measures to reduce exposures to as low as reasonably achievable (ALARA principle) were implemented after a seminar held in April 1987 which was attended by representatives of the seven factories concerned. Statistically significant falls in mean 24-hour urinary MBOCA levels were observed in follow-up levels in the five factories for which 'post-seminar' levels were measured.