BASED ON AVAILABLE DATA, CAN WE PROJECT AN ACCEPTABLE STANDARD FOR INDUSTRIAL USE OF ASBESTOS? NO Anders Englund
Foundationfor Industrial Safety and Health in the Construction Industry Bygghalsan, Fack. S-100 41 Stockholm, Sweden
A recent editorial in The Lancet reflects the increasing concern in the general medical community (not only those in occupational health) toward adverse health effects of asbestos and a need for strict regulation.’ The recent IARC monograph on asbestos concludes, based on experimental and epidemiologic data, that “it is not possible to assess whether there is a level of exposure in humans below which an increased risk of cancer would occur.”* I n a recent review in The Lancer. Dr. Julian Pet0 discusses the strength and weakness in arguments for defining a safe level of asbestos exposure.’ He finds such a definition more difficult in relation to neoplasia than to fibrosis. Moreover, different occupations might lead to quite different characteristics of exposure and, accordingly, different risks. Available exposure information is not comprehensive, and several areas of usage are totally unexamined with regard to dust level or disease pattern. Research conducted by Dr. I. J. Selikoffs group has demonstrated mesothelioma cases among groups with very low asbestos exposure, like family members! The observed interaction between smoking and asbestos in the causation of lung cancer has long been interpreted as “no smoking-no asbestos-related respiratory cancer.” In a recent review of several scientific reports, Saracci suggests that the data indicates a multiplicative interaction between asbestos and smoking.’ In recent testimony to the OSHA Cancer Standard Hearing, Dr. Selikoff underlined his strong doubts about the ‘‘no smoking-no risk” concept.6 It should be added that no influence of smoking on the appearance of mesothelioma has yet been demonstrated. My reasons for a negative answer to the question posed by the title of this paper are just as much based on domestic experience from the work sites. As Dr.Paul Kotin has remarked, standard setting is a social decision. My two motives are that asbestos use is wide spread, as are its biologic effects, and that wide use is not necessary to achieve present technologic aims in the society. Construction workers in general are not supposed to be heavily exposed to asbestos. Still, in one of our Swedish study areas, 410 workers reported they had been I ) . X-rays of these men showed pleural plaques in handling asbestos products (TABLE 130 and parenchymal fibrosis in 1 1 cases. In this special situation, I interpret this observation as an indirect indication of exposure. The 1 1 workers with parenchymal changes had mainly been plumbers, pipefitters, and insulators, while a substantial portion of the 130 men with pleural changes had been working as carpenters, concrete workers, and electricians. Another Swedish study, conducted by Dr. J. Stjernberg, found pleural changes in almost every second construction worker examined, although their degree of exposure was expected to have been low compared to, for instance, shipyard workers. A number of them, for instance, were painters. In a study of about 20,000 plumbers and pipefitters who joined the trade long ago, with a 5-year follow-up on cancer incidence and an 8-year followup on mortality
219 0077-8923/79/033&02I9~l.75/0 Q 1979, NYAS
220
Annals N e w
York Academy of Sciences
TABLE1 OCCUPATIONAL GROUPSWITH ABNORMAL LUNGX-RAY FINDINGS Number of workers with more than 3 months of asbestos exposure Abnormal x-ray findings Parenchymal fibrosis Pleural changes Carpenters Concrete workers Plumbers Insulators Electricians Painters Miscellaneous
410 141 11 130 44
21 24 4 12 8 17
(TABLE2), we found an almost two fold excess of respiratory cancers, including those of the nasal sinuses (five instead of one sinus tumor). The degree of asbestos exposure of these men is not yet known in detail, but a common operation for such men includes stripping of old insulation. There have been several public debates in Sweden regarding restriction of the use of asbestos, the last ones in 1972 and 1975. In a recent report, the arguments put forward by different interest groups (unions, manufacturer associations, political parties) have been analyzed. It is quite evident on both sides, workers’ union and manufacturer, that those who represent consumers (building and construction trades) express more concern about adverse health effects than do those from the producer trades. Also, the consumer representatives on both sides envisage alternatives to asbestos-based products, while producers consider asbestos to be absolutely necessary. The market has changed as a result of more strict regulations and the higher costs, involved in satisfying the new laws. Imports to Sweden of raw asbestos have fallen from 20,000 tons per year to almost zero in a few years (FIGURE I). Still, some importing of asbestos products remains, but it is expected to decrease. The changeover to alternative materials occurred very rapidly. To sum up, my reasons for giving the negative answer to the question are three fold: According to available scientific data, no safe level of exposure to asbestos with regard to neoplasia can be predicted with certainty, and the common saying “no TABLE2 A N D CANCER INCIDENCE AMONG PAINTERS AND PLUMBERS MORTALITY I N THE SWEDISH HOUSE-BUILDING TRADE ~~~~
Diagnosis Occupation Laryngeal cancer (161) painters plumbers Laryngeal cancer (161) Pulmonary cancer (162) plumbers Pulmonary cancer (162) plumbers
~
Source of Information Observed cancer registry 14 8 cancer registry cancer registry 38 72 cause of death certificate
Expected SMR p Value 1.77 0.03 8 3 2.46 0.02 1.61 0.002 24 38 1.89
Foundationfor Industrial Safety and Health in the Construction Industry Bygghalsan, Fack. S-100 41 Stockholm, Sweden
A recent editorial in The Lancet reflects the increasing concern in the general medical community (not only those in occupational health) toward adverse health effects of asbestos and a need for strict regulation.’ The recent IARC monograph on asbestos concludes, based on experimental and epidemiologic data, that “it is not possible to assess whether there is a level of exposure in humans below which an increased risk of cancer would occur.”* I n a recent review in The Lancer. Dr. Julian Pet0 discusses the strength and weakness in arguments for defining a safe level of asbestos exposure.’ He finds such a definition more difficult in relation to neoplasia than to fibrosis. Moreover, different occupations might lead to quite different characteristics of exposure and, accordingly, different risks. Available exposure information is not comprehensive, and several areas of usage are totally unexamined with regard to dust level or disease pattern. Research conducted by Dr. I. J. Selikoffs group has demonstrated mesothelioma cases among groups with very low asbestos exposure, like family members! The observed interaction between smoking and asbestos in the causation of lung cancer has long been interpreted as “no smoking-no asbestos-related respiratory cancer.” In a recent review of several scientific reports, Saracci suggests that the data indicates a multiplicative interaction between asbestos and smoking.’ In recent testimony to the OSHA Cancer Standard Hearing, Dr. Selikoff underlined his strong doubts about the ‘‘no smoking-no risk” concept.6 It should be added that no influence of smoking on the appearance of mesothelioma has yet been demonstrated. My reasons for a negative answer to the question posed by the title of this paper are just as much based on domestic experience from the work sites. As Dr.Paul Kotin has remarked, standard setting is a social decision. My two motives are that asbestos use is wide spread, as are its biologic effects, and that wide use is not necessary to achieve present technologic aims in the society. Construction workers in general are not supposed to be heavily exposed to asbestos. Still, in one of our Swedish study areas, 410 workers reported they had been I ) . X-rays of these men showed pleural plaques in handling asbestos products (TABLE 130 and parenchymal fibrosis in 1 1 cases. In this special situation, I interpret this observation as an indirect indication of exposure. The 1 1 workers with parenchymal changes had mainly been plumbers, pipefitters, and insulators, while a substantial portion of the 130 men with pleural changes had been working as carpenters, concrete workers, and electricians. Another Swedish study, conducted by Dr. J. Stjernberg, found pleural changes in almost every second construction worker examined, although their degree of exposure was expected to have been low compared to, for instance, shipyard workers. A number of them, for instance, were painters. In a study of about 20,000 plumbers and pipefitters who joined the trade long ago, with a 5-year follow-up on cancer incidence and an 8-year followup on mortality
219 0077-8923/79/033&02I9~l.75/0 Q 1979, NYAS
220
Annals N e w
York Academy of Sciences
TABLE1 OCCUPATIONAL GROUPSWITH ABNORMAL LUNGX-RAY FINDINGS Number of workers with more than 3 months of asbestos exposure Abnormal x-ray findings Parenchymal fibrosis Pleural changes Carpenters Concrete workers Plumbers Insulators Electricians Painters Miscellaneous
410 141 11 130 44
21 24 4 12 8 17
(TABLE2), we found an almost two fold excess of respiratory cancers, including those of the nasal sinuses (five instead of one sinus tumor). The degree of asbestos exposure of these men is not yet known in detail, but a common operation for such men includes stripping of old insulation. There have been several public debates in Sweden regarding restriction of the use of asbestos, the last ones in 1972 and 1975. In a recent report, the arguments put forward by different interest groups (unions, manufacturer associations, political parties) have been analyzed. It is quite evident on both sides, workers’ union and manufacturer, that those who represent consumers (building and construction trades) express more concern about adverse health effects than do those from the producer trades. Also, the consumer representatives on both sides envisage alternatives to asbestos-based products, while producers consider asbestos to be absolutely necessary. The market has changed as a result of more strict regulations and the higher costs, involved in satisfying the new laws. Imports to Sweden of raw asbestos have fallen from 20,000 tons per year to almost zero in a few years (FIGURE I). Still, some importing of asbestos products remains, but it is expected to decrease. The changeover to alternative materials occurred very rapidly. To sum up, my reasons for giving the negative answer to the question are three fold: According to available scientific data, no safe level of exposure to asbestos with regard to neoplasia can be predicted with certainty, and the common saying “no TABLE2 A N D CANCER INCIDENCE AMONG PAINTERS AND PLUMBERS MORTALITY I N THE SWEDISH HOUSE-BUILDING TRADE ~~~~
Diagnosis Occupation Laryngeal cancer (161) painters plumbers Laryngeal cancer (161) Pulmonary cancer (162) plumbers Pulmonary cancer (162) plumbers
~
Source of Information Observed cancer registry 14 8 cancer registry cancer registry 38 72 cause of death certificate
Expected SMR p Value 1.77 0.03 8 3 2.46 0.02 1.61 0.002 24 38 1.89
