Applications of biological monitoring in occupational health practice: practical application of urinary 2-ethoxyacetic acid to assess exposure to 2-ethoxyethyl acetate in large format silk-screening operations.

A practical application of urinary 2-ethoxyacetic acid (EAA) to assess occupational exposure to 2-ethoxyethyl acetate (EGEE-Ac) during a large format silk-screening operation is described. Industrial hygiene air monitoring of employees of a silk-screen shop producing large aircraft interior panel coverings revealed a broad range of exposures to EGEE-Ac. Time weighted exposures averaged 12 ppm (range 2.9-34 ppm) in press operators during production press runs, exceeding the 5 ppm Washington State permissible exposure limit. Employees were instructed to use organic vapor respirators until engineering controls could be developed. Urinary monitoring of EAA was conducted on 30 employees by the company medical department to aid in exposure risk assessment and to assess compliance. Results obtained ranged from 1.1-27 mg EAA/g creatinine which compares favorably with the proposed Biological Exposure Index (BEI) of 100 mg EAA/g creatinine. Results of representative air and biological monitoring, and observations of work practices for different exposure groups indicated that inhalation exposure was the predominant route of exposure. Follow-up testing to assess the efficacy of a newly installed ventilation upgrade is planned.