Hazardous Site Health Evaluation Program


Mortality Experience of Residents Exposed to Elevated Indoor Levels of Radon from an Industrial Source

For the full text of this study, please write to the New Jersey Department of Health and Senior Services, Consumer and Environmental Health Services, PO Box 360, Trenton, New Jersey, 08625-0360.


Forty-five homes in Montclair, Glenridge, and West Orange, Essex County, New Jersey were documented in the winter of 1983-1984 to have indoor radon gas concentrations in excess of Federal and New Jersey guidelines. The neighborhoods of the 45 houses were originally monitored by the New Jersey Department of Environmental Protection and the U.S. Environmental Protection Agency because radium waste from a former radium processing plant had been found there.

Lung cancer, which usually is fatal, was the focus of a mortality study because it is the only disease known to be associated with radon exposure. This is a study of the mortality rates (death rates) of those who lived for at least a year in any of those homes. The time-frame for the study spanned several decades, beginning from the early 1920's and ending in 1983. Death certificates, which are public record with causes of death recorded in a standard format nationwide, were sought and analyzed. Residency histories, vital status and causes of death (if deceased) for all individuals who had ever lived in any of these 45 homes for at least on year were collected for the study. Data were collected for more than 90 percent of the persons in the study group. Standardized mortality ratios (SMRs) group with the number expected based on death rates of United States or New Jersey populations according to age, sex, race, time period, and causes of death.

A higher rate of death due to lung cancer was found for white males in the study group when compared to the expected death rate from lung cancer for white males in both the United States and in the New Jersey populations. However, because of the small size of the study group, this difference is too small to rule out chance as a possible explanation. Furthermore, the inability to collect smoking histories or complete occupational histories prevent the consideration of smoking or occupation as contributors to the observed difference. Additionally, most of the lung cancer occurred among those white males who had lower indoor radon exposure than most others in the study group. Nevertheless, it is interesting to know that the degree of excess which is seen among white males is within the range predicted by the many occupational studies of lung cancer mortality among underground miners. For all other groups, no excess lung cancer was observed.

Other causes of death were also investigated, and are presented in the report. While various increases or decreases from the expected rates were observed, none of them appear to be causally related to radiation exposure.

Our study was initiated before the problem of naturally-occurring indoor radon was known to be widespread in the nation, and especially New Jersey. We now know that exposures from naturally-occurring sources are quite common and often exceed concentrations measured in most the 45 study houses before they were remediated.

The outcome of this study does not suggest any changes in the existing health recommendations for indoor radon exposure. The current guidelines apply to both industrial and natural sources of radon. They are based on strong human data and have been used both statewide and nationwide. Indoor radon exposure from natural sources can present a serious hazard for the general population. The New Jersey Department of Health recommends that homes be tested for radon and that elevated levels in home be reduced as low as is feasible.

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Last Updated: October 14, 1997