Multicentric study on malignant pleural mesothelioma and non-occupational exposure to asbestos
C Magnani, A Agudo, CA González, A Andrion, A Calleja, E Chellini, P Dalmasso, A Escolar, S Hernandez, C Ivaldi, D Mirabelli, J Ramirez, D Turuguet, M Usel and B Terracini

Cancer Epidemiology Unit, S Giovanni B Hospital and Regional Centre for Cancer Epidemiology and Prevention, Torino, Italy; Department of Epidemiology and Cancer Registration, Catalan Institute of Oncology (ICO), Av. Gran Via s/n, Km 2.7, E-08907, L’Hospitalet de Llobregat, Spain; Department of Pathology, Ospedale Martini, Torino, Italy; entre de Seguretat i Condicions de Salut en el Treball (CSCST), Barcelona, Spain; Epidemiology Unit, Center for Study and Prevention of Cancer Firenze (CSPO), AO Careggi, Firenze, Italy; Department of Preventive Medicine and Public Health, Hospital Universitario Puerta del Mar, Cádiz, Spain; Agency for Environmental Protection (ARPA) Piemonte, Torino, Italy; Department of Pathology, Hospital Clinic, Barcelona, Spain; Former Documentation Services, Instituto Nacional de Seguridad e Higiene en el Trabajo, and Centro de Investigación y Desarrollo de Barcelona (CSIC), Barcelona, Spain; Geneva Medical Inspectorate of Factories (OCIRT) and Geneva Cancer Registry, Geneva, Switzerland

Summary Insufficient evidence exists on the risk of pleural mesothelioma from non-occupational exposure to asbestos. A population-based case–control study was carried out in six areas from Italy, Spain and Switzerland. Information was collected for 215 new histologically confirmed cases and 448 controls. A panel of industrial hygienists assessed asbestos exposure separately for occupational, domestic and environmental sources. Classification of domestic and environmental exposure was based on a complete residential history, presence and use of asbestos at home, asbestos industrial activities in the surrounding area, and their distance from the dwelling. In 53 cases and 232 controls without evidence of occupational exposure to asbestos, moderate or high probability of domestic exposure was associated with an increased risk adjusted by age and sex: odds ratio (OR) 4.81, 95% confidence interval (CI) 1.8–13.1. This corresponds to three situations:
cleaning asbestos-contaminated clothes, handling asbestos material and presence of asbestos material susceptible to damage. The estimated OR for high probability of environmental exposure (living within 2000 m of asbestos mines, asbestos cement plants, asbestos textiles, shipyards, or brakes factories) was 11.5 (95% CI 3.5–38.2). Living between 2000 and 5000 m from asbestos industries or within 500 m of industries using asbestos could also be associated with an increased risk. A dose–response pattern appeared with intensity of both sources of exposure. It is suggested that low-dose exposure to asbestos at home or in the general environment carries a measurable risk of malignant pleural mesothelioma. © 2000 Cancer Research Campaign

Keywords: asbestos; environmental exposure; mesothelioma; case–control studies

There is convincing evidence that pleural malignant mesothelioma is associated with occupational exposure to all commercial forms of asbestos (Landrigan, 1998; WHO, 1998). Although most cases of mesothelioma show a definite history of asbestos exposure at work, in population studies there is a proportion of cases that do not report any occupational exposure throughout their working life. Therefore, attention has turned to the potential risk associated with exposure at the lower doses in the general environment (Landrigan 1998).

Two circumstances for possible non-occupational exposure to asbestos have been investigated: domestic and environmental exposure. The former results from asbestos fibres brought home by workers exposed in the workplace (Gardner and Saracci, 1989). Environmental exposure may result from residence in the vicinity of asbestos mines, mills, or factories using asbestos. In many studies there is a single well-identified source of asbestos pollution termed a ‘neighbourhood exposure’. Another kind is due to residence in areas where the soil is naturally rich in asbestos or similar fibres. Both sets of circumstances have led to localized outbreaks of pleural mesotheliomas, large enough to be first recognized in the absence of formal epidemiological studies (Gardner and Saracci, 1989). The latter are needed, however, to investigate whether the industrial use of asbestos may produce sufficient environmental pollution to cause asbestos-related disease. Rarely, mesotheliomas may occur in recognizable geographical or temporal clusters when the exposure is relatively high, but they will go unnoticed when exposure is low. Although asbestos is widely found in the environment, insufficient evidence exists on the risk of mesothelioma as a consequence of general environmental exposure (Siemiatycki and Boffeta, 1998). The extent to which the general population is exposed and the potential effects of such low-dose exposure are a matter of controversy.

A multicentric population-based case–control study was therefore carried out with the main aim of measuring risk associated with low-intensity, non-occupational exposure to asbestos.

A 10-year-old boy appears at your office with a chief complaint of shortness of breath. Exertional dyspnea has been present for the previous month and is associated with intermittent dry cough. The patient has no associated fever, chills, or chest pain. Chart review indicates no history of asthma or other pulmonary disease, although the patient has been seen several times for “hay fever.”

The patient is accompanied by his mother, who appears quite anxious. The mother emotionally relates that her 65-year-old cousin has recently been diagnosed with mesothelioma and is dying. Furthermore, he had been a custodian at the patient’s school for the previous 3 years, after retiring from his career as a longshoreman. His work at the school involved general cleanup and boiler room maintenance. The mother is afraid that her son’s dyspnea and cough are related to asbestos exposure at the school and that he might be developing mesothelioma, because he often helped her cousin after school. Recent asbestos removal in the school boiler room has increased the mother’s concern.

On physical examination, the patient is in no acute distress. Respirations are unlabored. Lung auscultation reveals a diffuse, expiratory wheeze. Spirometry performed in the office shows a forced vital capacity (FVC) of 95% of predicted value and a forced expiratory volume in 1 second (FEV1) of 88% of predicted value, with an FEV1/FVC of 70%. The remainder of the examination is within normal limits. A chest radiograph is normal.

1. PURPOSE

This procedure addresses two issues relating to asbestos containing materials (ACMs): ACM found in equipment and parts and ACM found in building materials. The proper procedure for the handling of ACM such as gaskets, set screw packing, geothermal valve packing, geothermal wellhead casing packoff materials, and other potential ACMs found in equipment being repaired, refurbished, or scrapped is discussed along with procedures for handling asbestos in building materials.

This procedure is designed to ensure that employee exposure to asbestos fibers is minimized or eliminated and that ACM is removed, stored, and disposed of properly during the repair, refurbishment, or scrapping of equipment. In addition, procedures are established for preparing for demolition or renovation activities in buildings, shops, warehouses, and other structures that may contain ACM.

2. SCOPE

This procedure applies to all Company employees and contractors who may come into contact with ACM while performing work on equipment. This procedure also addresses demolition or renovation activities in structures or buildings that contain
ACM as defined in the Asbestos NESHAP (40 CFR Part 61, Subpart M).

NOTE: It is the policy of COMPANY that no demolition or renovation activities occur in any owned or leased office buildings, warehouses, shops, or other buildings without the prior approval of the HSE Department. Under no circumstances shall any employee or contractor hired by COMPANY demolish or renovate building materials without first obtaining approval from the HSE Department. Approval will be dependent upon sampling and analysis of the building materials planned for renovation.

3. RESPONSIBILITIES

3.1 Department Supervisor or District Manager
a. Understand this procedure and communicate the information in the procedure to employees.
b. Train employees on the hazards of asbestos and ACM work procedures.
c. Ensure no renovation or demolition activities occur to building materials without prior approval.
d. Ensure ACM is properly stored and disposed of according to state and local regulations.

3.2 HSE Coordinator
a. Identify gasket and packing materials that are ACM through sampling and analysis or review of purchased materials.
b. Assist Department Supervisor or District Manager with implementation of this procedure, including training and proper disposal of ACM.