Use of Urine Samples to Assess and Control Exposures to 4,4'- Methylene Dianiline in the Aerospace Industry.
Boeniger-M; Mason-R; Hetcko-J; Jennings-T; Vernon-J; Cocker-J; Peterson-J
Proceedings of the Conference on Advanced Composites, American Conference of Governmental Industrial Hygienists, Inc., Cincinnati, Ohio 1992:87-111
The use of urine monitoring for evaluating and controlling 4,4'- methylene-dianiline (101779) (MDA) exposures in the aerospace industry was discussed. The uses of MDA and its toxicological properties were summarized. Routes of MDA absorption, metabolism, and elimination were discussed. MDA is absorbed primarily through the skin. MDA is acetylated to a considerable extent in humans and excreted in the urine as acetylated metabolites and free MDA. The results of industrial hygiene surveys of MDA exposures at three aerospace facilities were discussed. The surveys involved collecting personal air, wipe, bulk, glove, and urine samples for MDA analysis and observing work practices. Analysis of urinary MDA excretion enabled identification of exposed workers when air sampling data indicated that airborne MDA concentrations were below the proposed OSHA standard of 81 micrograms (microg) per cubic meter, especially at a site where only wet MDA or MDA flakes were used. Virtually no airborne MDA was detected at this facility. The highest urine MDA concentrations, ranging up to 460microg per liter, were detected in workers at the factory where only wet MDA or MDA flakes were used. Although workers at all three facilities were observed wearing gloves and coats made of impervious materials, detection of MDA in their urine samples and gloves indicated that they were not protected from exposure. Wearing the same gloves for prolonged periods without changing them was judged to be a contributing factor to the increased MDA absorption. A return visit to one facility where improvements in worker protection such as replacing latex gloves with laminated gloves and changing gloves frequently were made indicated that MDA exposures were sharply reduced, as evidenced by a more than 80% decrease in urinary MDA excretion.
Arylamines; Occupational-exposure; Aerospace-industry; Urinalysis; Biological-monitoring; Industrial-processes; Control-methods; Industrial-hygiene; Protective-clothing;
Proceedings of the Conference on Advanced Composites, American Conference of Governmental Industrial Hygienists, Inc., Cincinnati, Ohio