TYLER ASBESTOS WORKERS - MORTALITY EXPERIENCE IN A COHORT EXPOSED TO AMOSITE

Objectives-To examine the causes of death among 1130 former workers of a plant in Tyler, Texas dedicated to the manufacture of asbestos pipe insulation materials. This cohort is important and unusual because it used amosite as the only asbestiform mineral in the production proces s. High level exposure of such a specific type was documented through industrial hygiene surveys in the plant.Methods-Deaths were ascertaine d through various including data sources tapes from the Texas Departme nt of Health and the national death index files. As many death certifi cates as possible were secured (304/315) and cause of death assigned. After select exclusions, 222 death certificates were used in the analy sis. Causes of death were compared with age, race, and sex specific mo rtalities for the United States population with a commercial software package (OCMAP Version 2.0). Results-There was an excess of deaths fro m respiratory cancer including the bronchus, trachea, and lung (standa rdised mortality ratio (SMR) 277 with 95% confidence interval (95% CI) 193 to 385). Four pleural mesotheliomas and two peritoneal mesothelio mas were identified. The analysis also showed an increasing risk of re spiratory malignancy with increased duration of exposure including a s ignificant excess of total deaths from respiratory cancer with less th an six months of work at the plant (SMR 268 with 95% CI 172 to 399). C onclusions-The importance of the cohort lies with the pure amosite exp osure which took place in the plant and the extended period of latency which has followed. The death certificate analysis indicates the path ogenicity of amosite, the predominant commercial amphibole used in the United States. These data confirm a link between amosite asbestos and respiratory malignancy as well as mesothelioma.