Based on resident feedback and studies on the effects of benzene from gas stations near residences, SUN, as stated in the November SUN Spot, has taken an official position opposing the 14-pump gas station in Eastbridge.

The proposed gas station in Eastbridge would be 25 meters from income-qualified housing. The locations of three out of the four gas stations built as part of the Stapleton redevelopment are within 100 meters of housing*. Yet 89 percent of all respondents in a recent SUN survey said a gas station should be at least 300 feet (91.4 meters) away from any homes or daycares.

The proven causal relationship between benzene and cancer is well documented and accepted by the scientific community—and gas stations are classified by the Environmental Protection Agency as a point source for benzene. However, the distance from a gas station at which benzene levels become similar to urban background levels depends on several factors including vapor recovery methods used, the volume of gas pumped from a station, spills during fueling, and the meteorological conditions.

A link between childhood leukemia and residence within 100 meters of a gas station was shown in a 2004 study on a French cohort and published in the Occupational and Environmental Medicine journal; and researchers in Spain have measured refueling-related benzene 75 meters from a 6-pump gas station.

At the November 13th Denver Environmental Health (DEH) board meeting, Gregg Thomas, an environmental scientist at DEH, presented the data shown in Panel A (above). The DEH modeling indicated that within 60-90 meters of I-70 the concentration of benzene drops rapidly. He then stated that specific site plans for gas stations could reduce the off-site effects of any pollutants, and suggested that, where possible, the stations be located in a way that minimizes the potential for off-site effects. When this suggestion was presented, it was noted that the city has no authority over the site plan of a gas station in a “right by use” situation (privately owned land where zoning allows gas stations).

Thomas added that he does not believe the health risks from benzene emissions on nearby residents are sufficient to justify a citywide setback requirement.

At the same meeting, this author, on behalf of SUN, presented the data from Panel B (above right), which similarly shows a marked drop-off around 90-100 meters, with two caveats: 1) risks would be higher in Colorado because our gasoline is not reformulated (and therefore has more benzene), shifting both curves up, and 2) the risk would be between the two curves due to differences in vapor recovery methods between California and Colorado.

In addition, John L. Adgate, PhD, MSPH, Chair of the Department of Environmental and Occupational Health, Colorado School of Public Health, submitted a letter to the DEH board saying, in part, “While there is a limited scientific basis with which to determine an appropriate minimal setback, the potential for human exposure to hazardous air pollutants is real and I concur with the position that some sort of minimum setback is needed to address the health and safety concerns of Denver residents living near these facilities.”

The DEH board’s decision, as written in a November 21 letter to Councilman Chris Herndon, was “at this time, the Board of Environmental Health is not making any recommendations regarding setback requirements for gas stations.” Although the DEH board is not making a recommendation at this time, SUN continues to advocate for protection by the city for the small minority of residents who would bear the additional health risk deemed insufficient to merit action by the city of Denver.

Two other recently-built neighborhoods in Denver (Lowry and Green Valley Ranch) have been built while avoiding having housing and gas stations at such close proximity.

Examples in other cities where zoning-mandated spacing exists to protect homeowners from the negative health effects of gas stations are Milford, CT where a gas station cannot be within 90 meters (300 ft) of housing; Raleigh, NC where city-level approval must be obtained if a gas station will be within 122 meters (400 ft) of housing; and Chicago, IL where neighbors within 46 meters (150 ft) must give approval before a gas station can be built within that distance.  Denver currently has nothing in its zoning code to require spacing between a gas station and housing. A text amendment to modify zoning code would need to be passed by City Council.

Amanda Allshouse is a Senior Research Instructor, Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Denver and on the Board of Directors of Stapleton United Neighbors.