The three-year study in Garfield County detected levels of chemicals such as trimethylbenzenes, aliaphatic hydrocarbons, and xylenes in the air. All those chemicals can have neurological or respiratory effects, the study said.
Those effects could include eye irritation, headaches, sore throat and difficulty breathing.
"Our results show that the non-cancer health impacts from air emissions due to natural gas development is greater for residents living closer to wells," the report said. "The greatest health impact corresponds to the relatively short-term, but high emission, well completion period."
Completions involve hydrofacturing, a process in which water, sand and trace chemicals are forced down the well under pressure to crack the rock to release more oil and gas and flowback, when the frack fluid and hydrocarbons return to the surface.