The researchers compared cancer rates of adults living within 2 miles and 2-5 miles from SSFL with those of adults living more than 5 miles away, in Ventura and Los Angeles counties. They found that from 1988 through 1995, residents living within 2 miles of SSFL had a 60% higher rate of cancers than the control group. These included cancers of the thyroid, oral and nasal cavities, pharynx, larynx, esophagus, and bladder, as well as blood cancers such as leukemia, lymphoma, and multiple myeloma.
In separate studies, the investigators found higher rates of certain cancers among workers at SSFL who were exposed to radiation and to hydrazine, a chemical in rocket fuel.
In an interview, Dr. Saro Armenian, a pediatric hematologist-oncologist who was not involved in the studies, said the 60% increase in cancer incidence, which translated into a 1.6-fold increase in risk, merits more investigation.
“In epidemiologic studies, a 1.6-fold risk is actually a pretty strong signal because typically, most signals that you get are somewhere around 1.1- to 1.2-fold increased risk,” noted Dr. Armenian, a specialist in pediatric cancer survivorship and outcomes at City of Hope National Medical Center in Duarte, Calif.
However, Dr. Thomas Mack, former director of the Los Angeles County Cancer Surveillance Program, contends that there is insufficient evidence to support a direct link between the 1959 reactor accident and recent incident cancers. Dr. Mack is currently a professor of preventive medicine and pathology at the University of Southern California in Los Angeles.
“I have evaluated concerns about local excesses of cancer at least 100 times, usually from county residents, but for a while I represented the CDC and the California cancer registry,” Dr. Mack said, in response to an emailed request for comment.
“So far I have seen no evidence of carcinogenic radionucleotides or chemical carcinogens from Santa Susana found in any meaningful amount in any nearby community, but if someone has such evidence that would constitute evidence, that needs a response,” Dr. Mack added.
Boeing and California
Boeing has said problems at SSFL were not responsible for the high cancer rates among children in the community.
In April 2007, in a statement opposing a bill before the California State Legislature that would compel Boeing to pay for SSFL site cleanup, the company said that “in contrast to the accusations made against The Boeing Company that falsely claim increased cancer rates in the communities surrounding SSFL, a recent study conducted by the University of Michigan School of Public Health just concluded the opposite.”
Yet as Dr. Morgenstern wrote in 2007 to California state Sen. Joe Simitian, then chair of the Committee on Environmental Quality: “For the period 1996 through 2002, we found that the incidence rate of thyroid cancer was more than 60% greater among residents living within 2 miles of SSFL than for residents living more than 5 miles from SSFL. The magnitude and consistency of the thyroid finding for both periods is especially provocative because of evidence from other studies linking thyroid cancer with environmental exposures originating at SSFL and found in the surrounding communities.”
Boeing chose to ignore the results and instead focused on the methods used in the study, where the authors acknowledged that they measured distance from the site rather than environmental exposures and thus could not conclusively link excess cancer rates to exposures arising from SSFL.
But Dr. Morgenstern emphasized the conclusion of the report: “Despite the methodologic limitations of this study, the findings suggest there may be elevated incidence rates of certain cancers near SSFL that have been linked in previous studies with hazardous substances used at Rocketdyne, some of which have been observed or projected to exist offsite.”