Arthur N. Rohl

Asbestos exposure during brake lining maintenance and repair

Abstract Data obtained on asbestos exposure of garage mechanics during brake lining maintenance and repair work show that fiber concentrations frequently in excess of regulated limits are common. The presence of chrysotile, ranging from 2 to 15%, in brake drum dusts, was demonstrated by X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and electron microprobe analyses. Unaltered chrysotile was found, both in fiber and fibril form, in air and brake drum dust samples. The chrysotile asbestos content of personal air samples, taken during automobile brake repair work, was measured both by optical and electron microscopic techniques. While a positive correlation exists between the types of measurements, the present technique of optically counting asbestos fibers may considerably underestimate the levels of total asbestos exposure.

Drywall construction and asbestos exposure

The rapid development of the drywall construction trade in the United States is described. It is estimated that some 75,000 U.S. construction workers are currently employed in this trade. The use of a variety of spackle and taping compounds is shown to be associated with significant asbestos exposure; air samples taken in the breathing zone by drywall tapers during sanding of taping compounds show fiber concentrations exceeding, by several times, the maximum level permitted by United States Government regulations. These findings are given together with the result of a clinical field survey of drywall construction workers demonstrating that asbestos disease may be an important health hazard in this trade.

ASBESTOS CONTAMINATION IN UNITED STATES SCHOOLS FROM USE OF ASBESTOS SURFACING MATERIALS

Until recently there was only limited awareness of the extent of asbestos use in public school buildings. Reports existed of damaged asbestos surfaces in a grade school in Wyoming,’ a university dormitory in California,’ and in the Yale School of Arts and Architecture in New Haven, C o n n ~ t i c u t . ~ In each case, public concern led to the removal of the asbestos material. In both the Wyoming school and the Yale Library, air measurements by optical microscopy showed asbestos concentrations that in some circumstances exceeded 5 f/ml, the time-weighted-average occupational standard in effect a t the time. In the fall of 1976, flaking of sprayed-on asbestos was reported in a school in Howell Township, New Jersey, leading to its removal and to further concern about the presence of deteriorating asbestos in other school buildings in New Jersey. As a consequence, the New Jersey Department of Education requested that the school administrators report the presence and condition of asbestos surfaces in all school buildings within the state. Responses revealed that 265 (of approximately 2400) schools in all 142 districts in the State had nearly three million square feet of what they considered to be asbestos material in classrooms, auditoriums, hallways and other rooms accessible to pupils.

Asbestos-related diseases. Algorithm for forensic pathological diagnosis.

The pathological diagnosis and proof of asbestos causation in environmental-occupational diseases is based on a spectrum of increasingly sophisticated determinations with greater confidence in detection of asbestos bodies and fibers. These include the following: pathology (histology) and/or thick smears of lung, microincineration, bulk chemical digestion, and electron beam instruments. The requisites of medical and forensic asbestos causation differ, and do not always require the full range of these analytical techniques. The need and significance of some of these determinations, as expressed in number of asbestos bodies and fibers, may be related in many cases to the evidence of asbestosis; to the gross and microscopic pathological findings (asbestosis, lung carcinoma, mesothelioma); the exposure history (type, duration, intensity, and period of latency); and nature of the asbestos mineral. An algorithm for the forensic pathological diagnosis of asbestosis and of asbestos-related diseases is proposed.