NIOSH dioxin registry site visit report of Rhone-Poulenc, Inc., Portland, Oregon, report no. IWS-117-14.
Worker exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (1746016) were assessed at Rhone Poulenc, Incorporated (SIC-2869), Portland, Oregon in January 1982. The survey was conducted to evaluate the feasibility of including workers involved with the synthesis of 2,4,5-trichlorophenoxyacetic-acid (93765) (2,4,5-T) in the dioxin (828002) registry. Complete personnel records were kept for all workers beginning in 1960. Limited medical information was available. Processes in the production of 2,4,5-T, its isooctyl and isobutyl esters, the formulation and packaging of its esters, and the production of its triethylamine salt were assessed. Formulation included blending the completed acids and esters and mixing the solutions to the proper strengths. Synthesis, dilution, and addition of additives and filtering were part of the formulation operation for amines. The same equipment was used for processing 2,4,5-T and 2,4-dichlorophenoxyacetic-acid (94757). No pressure releases or blow outs occurred during processing. No industrial hygiene data on worker exposures to process materials was available. No analysis for dioxin contamination or process contamination was available. The authors conclude that potential exposures to 2,4,5-T or other products derived from 2,4,5-trichlorophenol (95954) exist among the workers. The cohort of workers should be included in the dioxin registry.