Abstract  A nation-wide survey of the impact of point and nonpoint asbestos sources on waterborne asbestos levels identifies and evaluates seven natural asbestos-bearing sites, and 22 plants manufacturing asbestos products. Water samples were analyzed from five cities with water supplies from natural sites with high asbestos content, and from 12 cities with water supplies contaminated by manufacturing operations. Five major areas of the country were investigated: northern Vermont and New Hampshire; southern Montana; Washington-Oregon region; northern California; and the boundary region of Georgia, the Carolinas, and Tennessee. Three river systems were studied: the upper Connecticut, upper Red Rock and Beaverhead, upper Trinity, Little Tennessee, Hiwassee, and Chatooga-Savannah. The 22 plants sampled account for about 45% of the asbestos tonnage used in the United States, and include all major asbestos products--asbestos cement pipe, cement sheet, paper and millboard, roofing and tile, textiles, and friction materials. Effluent treatment varied from none through various settling and pH controls to total recycling. Waterborne asbestos levels originating from natural sources were as high as 100 million fibers/1, and fibers were usually less than 5 micrometers long. Asbestos from manufacturing ranged from undectable to over one trillion fibers/1. Asbestos paper plants constitute the most serious environmental hazard. (Lynch-Wisconsin)

Abstract  Over the last 30 years there has been a world wide increase in the incidence of malignant mesothelioma, mainly associated with prior exposure to asbestos dust. Mesotheliomas often present with recurrent serous effusions that are usually sent for cytological examination. This review documents the introduction, development and state of the art of cytopathology in the diagnosis of malignant mesothelioma.

Abstract  BACKGROUND: The incidence of malignant mesothelioma continues to increase, but the disease remains difficult to detect early and treat effectively. METHODS: The authors review the pathogenesis, incidence, clinical presentation, diagnosis, pathology, and both standard and experimental treatments for mesothelioma. RESULTS: When possible, surgery (video-assisted thoracoscopy, pleurectomy/decortication, or extrapleural pneumonectomy) is utilized. Effects on underlying structures limit application of radiation therapy, but some systemic agents are beginning to enhance survival. CONCLUSIONS: The disease is expected to increase in incidence till 2020, so awareness of this entity as a possible diagnosis should be heightened. In patients with advanced disease, several newer antitumor agents are already showing a capability of extending survival so it is not unreasonable to expect further progress in this area.

Abstract  This Risk Evaluation for Asbestos, Part 1: Chrysotile Asbestos (hereafter referred to as “Part 1” or “Part 1 of the risk evaluation”) for imported, processed and distributed uses of chrysotile asbestos was performed in accordance with the Frank R. Lautenberg Chemical Safety for the 21st Century Act and is being issued following public comment and peer review. The Frank R. Lautenberg Chemical Safety for the 21st Century Act amended the Toxic Substances Control Act (TSCA), the Nation’s primary chemicals management law, in June 2016. Under the amended statute, EPA is required, under TSCA Section 6(b), to conduct risk evaluations to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment, under the conditions of use, without consideration of costs or other non-risk factors, including an unreasonable risk to potentially exposed or susceptible subpopulations identified as relevant to the Risk Evaluation. Also, as required by TSCA Section 6(b), EPA established, by rule, a process to conduct these Risk Evaluations, Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act (82 FR 33726) (Risk Evaluation Rule). Part 1 of the risk evaluation is in conformance with TSCA Section 6(b) and the Risk Evaluation Rule and is to be used to inform risk management decisions. In accordance with TSCA Section 6(b), if EPA finds unreasonable risk from a chemical substance under its conditions of use in any final Risk Evaluation, the Agency will propose actions to address those risks within the timeframe required by TSCA. However, any proposed or final determination that a chemical substance presents unreasonable risk under TSCA Section 6(b) is not the same as a finding that a chemical substance is “imminently hazardous” under TSCA Section 7. The conclusions, findings, and determinations in Part 1 are for the purpose of identifying whether the chemical substance presents unreasonable risk under the conditions of use, in accordance with TSCA section 6, and are not intended to represent any findings under TSCA section 7.

Abstract  BACKGROUND: Potassium octatitanate fibers (K2O•8TiO2, POT fibers) are used as an asbestos substitute. Their physical characteristics suggest that respirable POT fibers are likely to be carcinogenic in the lung and pleura. However, previous 2-year inhalation studies reported that respired POT fibers had little or no carcinogenic potential. In the present study ten-week old male F344 rats were left untreated or were administered vehicle, 0.25 or 0.5 mg rutile-type nano TiO2 (r-nTiO2), 0.25 or 0.5 mg POT fibers, or 0.5 mg MWCNT-7 by intra-tracheal intra-pulmonary spraying (TIPS), and then observed for 2 years.

RESULTS: There were no differences between the r-nTiO2 and control groups. The incidence of bronchiolo-alveolar cell hyperplasia was significantly increased in the groups treated with 0.50 mg POT and 0.50 mg MWCNT-7. The overall incidence of lung tumors, however, was not increased in either the POT or MWCNT-7 treated groups. Notably, the carcinomas that developed in the POT and MWCNT-7 treated rats were accompanied by proliferative fibrous connective tissue while the carcinomas that developed in the untreated rats and the r-nTiO2 treated rats were not (carcinomas did not develop in the vehicle control rats). In addition, the carcinoma that developed in the rat treated with 0.25 mg POT was a squamous cell carcinoma, a tumor that develops spontaneously in about 1 per 1700 rats. The incidence of mesothelial cell hyperplasia was 4/17, 7/16, and 10/14 and the incidence of malignant mesothelioma was 3/17, 1/16, and 2/14 in the 0.25 mg POT, 0.5 mg POT, and MWCNT-7 treated groups, respectively. Neither mesothelial cell hyperplasia nor mesothelioma developed in control rats or the rats treated with r-nTiO2. Since the incidence of spontaneously occurring malignant mesothelioma in rats is extremely low, approximately 1 per 1000 animals (Japan Bioassay Research Center [JBRC] historical control data), the development of multiple malignant mesotheliomas in the POT and MWCNT-7 treated groups was biologically significant.

CONCLUSION: The incidence of pleural mesotheliomas in male F344 rats administered POT fibers and MWCNT-7 was significantly higher than the JBRC historical control data, indicating that the incidence of pleural mesothelioma in the groups administered POT fibers and MWCNT-7 fibers via the airway using TIPS was biologically significant. The incidence of type II epithelial cell hyperplasia and the histology of the carcinomas that developed in the POT treated rats also indicates that respirable POT fibers are highly likely to be carcinogenic in the lungs of male F344 rats.

Abstract  In mid-September, three additional papers were brought to the attention of the WATCH chair by a member as likely to be relevant to the asbestos discussion. The papers provide updated information about two of the cohorts included in the H&D analysis and one additional cohort. All these cohorts involved predominantly chrysotile exposure. This assessment made by HSE (Andy Darnton) provides a short discussion about each of the papers, plus some further details about the additional cohort. Copies of each of the papers are also attached. It then presents updated summary estimates for mesothelioma risk per unit of cumulative exposure and the results of refitting the H&D-type models for pleural mesothelioma.

Abstract  BACKGROUND: A recent analysis indicates that the excess odds ratio for lung cancer by smoking is described by a function that is linear in pack-years and exponential in the logarithm of smoking intensity and its square (Cancer Epidemiol Biomarkers Prev. 2006;15:517-523). The model suggests that below 15-20 cigarettes per day there is a "direct exposure rate" effect, ie, the excess odds ratio per pack-year for higher intensity (and shorter duration) smokers is greater than for lower-intensity (and longer duration) smokers. Above 20 cigarettes per day, there is an "inverse-exposure-rate" effect, ie, the excess odds ratio per pack-year for higher intensity smokers is smaller than for lower-intensity smokers.

METHODS: Using pooled data from 2 large case-control studies of lung cancer (the European Smoking and Health Study and the German Radon Study), we evaluated effect modification of the association between smoking and lung cancer.

RESULTS: Interaction effects are very specific. Variations in risk of lung cancer with years since cessation of smoking, age, method of inhalation, and type of cigarette result from interactions with smoking intensity, and not total pack-years. In contrast, risk variations by sex result from the interaction with total pack-years, while intensity effects are homogeneous. Risk variations by age at which smoking started result from interactions with both total pack-years and intensity. All intensity interactions are homogeneous across studies.

CONCLUSIONS: The specificity of the interactions may provide clues for the molecular basis of the smoking and lung cancer relationship.

Abstract  On July 3, 1980 the National Health (NIOSH) received a request for a health hazard evaluation from a representative of the Civil Service Association, Local 400. The requester was concerned that storekeepers and mechanics working at the Department of Municipal Railway (Woods Division) may be exposed to toxic concentrations of diesel exhaust fumes. The employees complained of headaches, respiratory and eye irritation. NIOSH conducted an initial environmental survey on July 23, 1980 and a follow-up environmental/medical survey on September 23, 1980. Area air sampling was conducted on the first and second floors of the repair terminal for sulfur dioxide, formaldehyde, nitrogen dioxide, and carbon monoxide using direct reading colorimetric detector tubes. No sulfur dioxide, formaldehyde or nitrogen dioxide gas was detected. Carbon monoxide concentrations ranged from below the limits of detection to 7 ppm (parts of a vapor or gas per million parts of contaminated air). These concentrations were below the NIOSH recommended criteria (35 ppm). Three general area air samples were collected for total particulate. The concentrations measured were 0.07, 0.08i 0.13 mg/M3 (milligrams of particulate per cubic meter of air). All of these · concentrations were well below the California-Occupational Safety and Health Administration (CAL-OSHA) standard. Informal medical interviews were conducted with twelve day shift employees who worked in the administrative offices, storekeepers room (parts department) arid maintenance areas. Questions were asked regarding work history and recent symptoms of headache, eye, nose and throat and/or lung irritation. Workers were also asked about .possible exposures to diesel fumes and smoke. Complaints of eye and upper respiratory irritation, dizziness, headaches and odor irritation consistent with diesel exhaust exposures were reported, particularly in the storekeeping, brake relining and injector cleaning rooms where fumes are concentrated.