Cancer rates are normal for the residents of a southeast Minneapolis neighborhood with contaminated soil, the Minnesota Department of Health reported Tuesday.
That doesn’t mean residents of the Como neighborhood are free of health risks from the environmental contamination, which occurred from 1947 to 1962 when industrial solvents were dumped out back of an old General Mills plant. But it should give them “reassurance that cancer rates in this community are not unusual,” the report stated.
Using the ages and genders of residents in the 55414 ZIP code, the health department projected how many cancer cases they would expect to find and then counted how many cases were actually reported between 2001 and 2010. While 271 cancers were reported among men in that ZIP code during the decade, for example, the state would have expected 293 based on the community’s demographics.
Questions about health risks have persisted in the Como neighborhood immediately south and west of the former General Mills plant since November, when state pollution and health authorities announced the discovery of potentially harmful vapors in the soil from a toxin called trichloroethylene, or TCE. The volatile compound has been linked to cancer and other disorders when people are exposed to high levels for prolonged periods.
Pollution from the General Mills site was identified in the early 1980s, and the removal of TCE from the groundwater took place until 2010. But officials with the Minnesota Pollution Control Agency said it was only recently that scientists discovered how TCE could surface in soil vapor as well and potentially enter homes and businesses through cracks or openings in basements and foundations.
Testing of 143 homes and properties in the neighborhood have found troublesome levels of TCE below the foundations of 92. General Mills has paid for the installation of ventilation systems — identical to those used to remove radon — in at least 28 of those homes and is working with property owners to install others. Another 60 properties have yet to be tested, and in two cases property owners have refused testing.
Mitigation systems are being installed in homes where the TCE readings are above 20 micrograms per cubic meter. Results in 23 properties have produced TCE levels above 1,000, which might sound extreme but doesn’t suggest the need for a more urgent response, Jim Kelly, an environmental surveillance and assessment manager for the state health department, said in an e-mail.
“Levels of TCE are certainly higher beneath some homes than others,” he wrote, but “it mainly means that residents of some homes may have a slightly higher risk (but still low overall) of potential health effects.”
Health officials reported in November that there was no elevated rate of birth defects among families in the Como neighborhood. But studies of the cancer data took much longer partly because of turnover in the health department’s cancer epidemiology unit.
Health officials cautioned against drawing conclusions from the cancer study. The neighborhood has a relatively young and transient population — thanks in part to its proximity to the University of Minnesota — and the study didn’t track cancers among people who once lived in the neighborhood but had moved away.
Also, the study is a crude barometer of cancer risks in the immediate Como neighborhood. It included all cancers in a ZIP code that included the Marcy-Holmes and Prospect Park-East River Road neighborhoods.