The study found those living near oil and gas sites along the Northern Front Range may be exposed to hazardous air pollutants – including carcinogens like benzene – that could pose health risks above levels deemed acceptable by the U.S Environmental Protection Agency (EPA).
Researchers also found the lifetime cancer risk for those living within 500 feet of a well was eight times higher than the EPA's upper level risk threshold.
“We found that air pollutant concentrations increased with proximity to an oil and gas facility, as did health risks,” the study said. “Acute hazard indices for neurological, hematological and developmental health effects indicate that populations living within 152 meters (500 feet) of an oil and gas facility could experience these health effects from inhalation exposures to benzene and alkanes.”
Due to its findings, the study also raises questions about Colorado's current regulations that require a new a new oil and gas well to be 500 feet from a residence and 1,000 feet from schools or hospitals.
“Our results suggest that Colorado’s current regulations that specify a 500 foot distance between a newly drilled oil and gas well and an existing home may not protect people from exposures to hazardous air pollutants that could impact their health,” said the study’s lead author Lisa McKenzie, PhD, MPH, of the Colorado School of Public Health. “Our previous work shows that thousands of people along the Front Range of Colorado live closer than 500 feet from a well and related infrastructure and that the population living close to these facilities continues to grow.”
The study focused its research on emissions of non-methane hydrocarbons that oil and gas wells emit into the air, including, benzene, toluene, ethylbenzene and xylenes.
“The study provides further evidence that people living close to oil and gas facilities are at the greatest risk of acute and chronic health issues due to air pollutants emitted by those facilities,” said study co-author Pam Milmoe, Boulder County Public Health Air Quality Program Coordinator. “The results underscore the importance of having policies that require effective monitoring and reducing emissions from oil and gas facilities, particularly those near homes, schools, and recreation areas.
An energy industry representative disputed the report's findings.
"Previous health studies released by these authors, all of which seek to link health concerns to the state’s oil and gas industry, have drawn sharp criticism from the state’s top health regulators," said Rebecca Simons, with Energy in Depth Mountain States, who said that McKenzie's research has been questioned and at times discredited, pointing to 2017 findings from the Colorado Department of Public Health and Environment that studied homes 500 feet or more away from sites.
Similarly, the Colorado Oil and Gas Association pointed to the COGCC's 500-foot rule and said McKenzie had been involved in other "inflammatory analysis" in the past.
The CDPHE's executive director and chief medical officer, Dr. Larry Wolk, told Denver7 Monday that the new study "confirms our 2017 findings of low risk for cancer and non-cancer health effects at distances 500 feet and greater."
He additionally said that the CDPHE study used "many" of the same datasets as the department did, along with "similar" methods. But he said there were two differences between the studies.
First, the CU study looked at data involving readings closer than 500 feet, while the CDPHE study only looked at data beyond 500 feet because that is the COGCC's current rule for setbacks. Second, Wolk said, the CU study used California EPA risk assessments while the CDPHE used EPA standard methodology.
That being said, Wolk said the CU study underscores the importance of the 500-foot setback rule, and said the CDPHE had so far "not found any elevated short or long-term risks from the same substances evaluated in the McKenzie study."
Wolk said a new risk assessment using newer data from Colorado State University was being put together in the meantime that should help contextualize both studies.