Thank you for the opportunity to address the Senate Committee on the Judiciary on the subject of the Radiation Exposure Compensation Act. I am Jonathan M. Samet, M.D.,M.S., from Baltimore, Maryland. I am presently Professor and Chair of the Department of Epidemiology of the Johns Hopkins University School of Hygiene and Public Health. My professional background is in the subspecialty of pulmonary diseases and in the research discipline of epidemiology, the study of disease in populations. Before coming to Johns Hopkins in 1994, I was a faculty member in the Department of Medicine of the University of New Mexico School of Medicine in Albuquerque. During the 16 years that I spent in New Mexico, beginning in 1978, the health consequences of uranium mining were a principal focus of my research, and I also had substantial experience in providing clinical care for many former underground uranium miners suffering from lung cancer and silicosis. My research group investigated the problem of lung cancer in former Navajo miners and conducted a major epidemiological study on risks of lung cancer and other diseases in the men who worked in the Grants uranium belt. We also completed the study of non-malignant respiratory disease in uranium miners for the Centers for Disease Control that was mandated by the Radiation Exposure Compensation Act. I have served on a number of expert groups concerned with the health effects of radon exposure including the Biological Effects of Ionizing Radiation (BEIR) IV Committee of the National Research Council, the Radon Dose Panel of the National Research Council, and the BEIR VI Committee, which I chaired.

I have previously testified on issues related to the Radiation Exposure Compensation Act in a hearing of the Committee on Labor and Human Resources of the Senate on June 5, 1993. A copy of that testimony is attached. Additionally, following a request from Senator Hatch, I prepared an evaluation of aspects of the Radiation Exposure Compensation Act, including the need for expansion of coverage of cancer for the persons exposed downwind of the nuclear blast, and I also addressed issues related to the uranium miners. A copy of my letter to Senator Hatch, dated May 1, 1997, is also included with this testimony.

I am in full agreement with the intent and purpose of the Radiation Exposure Compensation Act. The two major epidemiologic studies of lung cancer in underground uranium miners in the United States, the study initiated by the Public Health Service of Colorado Plateau miners and the study of New Mexico miners, both show tragic elevations in lung cancer risk, approximately 400% of expectation. The studies also document excess deaths from non-malignant respiratory diseases. Unfortunately, the lung cancer excess in the New Mexico miners, who generally started work at least a decade after the Public Health Service group, has not been any lower than for the original Colorado Plateau miners.

Appropriately, the Radiation Exposure Compensation Act offers an apology and compensation to the underground uranium miners and others exposed to radiation from activities of the federal government. I understand that problems have arisen in its implementation, but the Act is complex in both its scientific and human bases. In this testimony, I will focus on concerns with regard to the provisions for underground uranium miners. I will also offer comments concerning the uranium millers. The letter to Senator Hatch offers my views on other aspects of the Radiation Exposure Compensation Act.
With regard to the uranium miners, I have three broad areas of concern:

Exposure requirements: The lung cancer risk in underground uranium miners arises from exposure to the radioactive progeny of radon. Our current understanding of the mechanisms by which radon causes lung cancer, as recently reviewed in the BEIR VI Report, indicates that the relationship between dose and risk is linear without a threshold; in other words, any exposure carries some risk and the risk rises in a straight line fashion with exposure. Thus, any level of radon should be considered to have contributed to the occurrence of lung cancer in underground miners. The probability that the lung cancer was caused by radon rises with the exposure. Given our deepening understanding of this exposure-risk relationship, the adoption of arbitrary cut-off values for compensation is inappropriate. Indeed, the present cut-off values are set quite high and require that underground miners must have received a substantially higher dose, than other persons compensated under the Act, in order to qualify. I have been unable to determine the specific data that led to the current thresholds for compensation.

An additional problem has arisen in implementing the exposure criteria. Not surprisingly, the historical record is incomplete on past exposures in the many mines that were scattered across the West. Few measurements were made in the early years when exposures were highest. The consequent problem of error in making estimates of exposure for the underground miners in Colorado and New Mexico has been well described. Given the imperfections of the exposure data, holding to firm criteria appears inappropriate and counter to the intent of the Radiation Exposure Compensation Act. Alternative approaches, driven by the analyses of the available data, were developed by the Radiation Exposure Compensation Act Committee, and offered in their July, 1996 report to the Human Radiation Interagency Working Group. However, I noted concerns with this report in my 1997 letter to Senator Hatch. I would favor allowing straight-forward alternatives to the present exposure requirements, such as requiring documentation of a certain length of time underground.

Persons who have never smoked should be handled as a special group, regardless, and provided compensation. For any former miner known to be a nonsmoker, the probability of causation for underground mining approaches 100% or almost full certainty. Our study of lung cancer in Navajo men, published in 1984, showed that the majority of cases that occurred among Navajo males between 1969 and 1982 was attributable to underground uranium mining. A 1994 report by the National Cancer Institute estimated that 87% of cases in never-smokers in the Public Health Service cohort could be attributed to occupational exposure; the corresponding figure for the New Mexico miners was 47%, likely reflecting imperfections of the data and the small number of never-smokers in the cohort who have so far developed lung cancer.

Provisions for smokers: In my letter to Senator Hatch, I comment on the penalty applied to smokers. There is a form of synergy between smoking and exposure to radon progeny, implying that smokers have enhanced risk for lung cancer if also exposed to the progeny of radon. The Act currently penalizes smokers for their addiction by requiring a higher level of exposure. Smokers will experience far more lung cancers than never-smokers, but their risk rises with exposure, just as does the risk for nonsmokers. In fact, the 1994 National Cancer Institute Analysis indicates that the majority of cases of lung cancer in the Colorado Plateau (attributable risk=59%) and New Mexico miner cohorts (attributable risk=74%) are attributable to exposure to radon progeny.

The inequity with regard to the exposure provisions needs to be removed for smokers. The Congress will need to be prepared to possibly cover the large number of cases that will occur in former uranium miners who also smoked, or perhaps entertain separate levels of compensation for smokers and never-smokers.

Non-malignant respiratory diseases: Underground uranium miners, like miners of many other types of ore, develop non-malignant respiratory diseases. One of these diseases is silicosis, the scarring disorder of the lung caused by inhalation of silica or sand. They may also develop a form of scarring or fibrosis that is non-specific and not clinically identical to silicosis. The existence of this entity has been controversial, but cases have been reported.

The occurrence of these diseases is not specifically linked to the level of exposure to radon progeny. Silicosis risk, of course, reflects the level of exposure to silica. Other noxious contaminants in the mines, such as blasting fumes and diesel exhaust, may also contribute to the problem of non-malignant respiratory diseases in the miners.

I recognize that the Act is directed at compensating for the consequences of radiation exposure. The occurrence of one disease, silicosis, reflects exposure to a factor other than radiation—silica. Exposures to silica and radon progeny were not necessarily correlated in the mines and for this reason, I would recommend removing the linkage of compensation for non-malignant respiratory diseases to the level of exposure to radon progeny.

Unfortunately, data on silica levels in the underground uranium mines are extremely limited and it will not be possible to develop estimates of silica exposure that could be used for the purpose of compensation. The presence of silicosis itself is evidence for exposure and I would suggest that compensation be based on the presence of a non-malignant respiratory disease associated with uranium mining alone. There will be difficulties with this approach, particularly for miners who had worked in mines other than underground uranium. Nonetheless, I think that a reasonable approach could be found.

With regard to the uranium millers, there has been little investigation of the health consequences of being a mill worker. The mills were complex operations involving exposures to radon progeny, uranium, and various chemicals. The surviving millers are concerned about their health and there is an urgent need to obtain information on health and disease in this population. The National Institute for Occupational Safety and Health undertook an initial, exploratory study with regard to the feasibility of an epidemiologic investigation of mortality, and the University of New Mexico School of Medicine is currently planning a survey. This evidence needs to be gathered quickly, as the former millers are now in their 50s and above.

In summary, the Radiation Exposure Compensation Act was well-intentioned, but experience with the Act over the eight years since its implementation indicates that revisions are needed. There is a need for harmonization of approaches to the various groups and the specific concerns that I have listed with regard to the underground uranium miners need to be addressed. There is some urgency for making these revisions as many of the former miners and their spouses are already elderly.