Occupational exposure to phthalic-anhydride (85449) (PA) and di(2- ethylhexyl)phthalate (117817) (DEHP) was determined in the urine of manufacturing workers. Approximately 30 percent of the PA produced at the factory was used in the production of DEHP; the remainder was pumped to tank cars and trucks and sold for use elsewhere. Personal sampling pumps were attached to the employees to determine exposure to airborne DEHP and PA. Group 1 included the chemical operators, mechanics, and tank farm operators exposed to higher concentrations of DEHP and PA. Group 2 included storekeepers, wastewater operators, boiler operators, quality control operators, instrument technicians, first line supervisors, and employees involved in administration, safety, engineering, and accounting work. The total phthalate concentration in urine was determined by gas chromatography after hydrolysis and conversion to dimethylphthalate (131113). A number of urine samples were also assayed for DEHP and for specific DEHP metabolites, including monoethylhexyl-phthalate (4376209) (MEHP). Of 50 personal samples obtained for DEHP, 6 contained concentrations above the limit of detection of 10 micrograms (microg) per sample; the time weighted average concentrations ranged from 20 to 4,110microg per cubic meter (m3). High concentrations of DEHP were found in five chemical operators. Exposure to measurable quantities of PA were found in all manufacturing processes in concentrations ranging from 4 to 203microg/m3. The mean urinary phthalate concentrations of the pre shift samples did not differ among the exposure groups. MEHP was not found in workers exposed to DEHP. There was a weak correlation between personal exposure to airborne PA and the total urinary phthalate concentration of the post shift samples. The authors suggest that measurement of urine phthalate concentrations appears useful for monitoring the exposure of workers manufacturing or using PA.