Colorado’s oil and gas regulators say they will start putting some drilling applications through a more rigorous review process after a study found people face short term health risks, such as headaches and dizziness, if they are within 2,000 feet of the wells.

The study released Thursday specifically found the health risks occur when a well is being constructed, with the highest risk coming at a time when a process called “flowback” occurs.

The findings have spurred the Colorado Oil and Gas Conservation Commission to extend the threshold for a more rigorous permit review process to wells that are within 2,000 feet of homes. Previously, the threshold was 1,500 feet.

Asked what message the state had for residents who already live within 2,000 feet of a well, Jeff Robbins, the head of the state board that reviews permit applications, said they should not be worried.

“For those wells that are already in the production phase, this study is not implicating any health impacts,” he said. “And that’s the vast majority of existing wells.”

Still, Robbins said he would start talking with oil and gas operators who are in the process of drilling wells within 2,000 feet of homes “to see if we can work with them to ensure protective measures are there on site.”

“They have a vested right to develop, because they have approvals,” he said.

Officials with the Colorado Department of Public Health and Environment also sought to get ahead of any concerns the study might generate.

They said the findings showed a risk of health effects only under “worst-case conditions.”

One example officials provided was if someone was running close to an oil and gas site while it was being constructed and there were also strong winds at the time.

Meanwhile, some elected officials are pointing to the study and its findings as reason to adopt more safeguards for drilling.

In a statement, Senate Majority Leader Steve Fenberg, D-Boulder, said the state needs to take “aggressive and immediate action” in response to the study.

He called on the Colorado Oil and Gas Conservation Commission to immediately stop considering any applications for wells that are within 2,000 feet of homes and schools, giving the state time to put stronger regulations in place to protect public health.

Oil and gas industry groups worked to play down the new findings. In a press conference held immediately after the CDPHE study’s release, they highlighted the researchers’ use of data from several years ago and their reliance on scientific modeling, instead of field monitoring.

Dan Haley, president of the Colorado Oil and Gas Association, said policy shouldn’t be based solely on its findings.

“This model uses data that uses open tanks and different things that haven't happened in the industry in three or four years,” Haley said. “We need policy based on current technology and real operational details.”

Lynn Granger, executive director of API Colorado, added her organization would evaluate the new findings and provide a more robust response in the coming days. She said past studies haven't indicated a need for an immediate public health response.

“As an industry we rely on data, facts and science and look forward to working with CDPHE and the COGCC on actual air monitoring in the future, which is what should be used when developing policy and regulations," she said.

Dr. Mike Lumpkin, a senior toxicologist with CTEH, an environmental consulting firm based in Little Rock, Arkansas, also spoke at the press conference. He called the study a “piece of the puzzle” when it comes to pinning down oil and gas’ impact on public health.

“This paper has done a really nice job at looking at a number of factors and it has given us some direction of what to look into with regard to potential health effects,” Lumpkin said. “But it has not identified actual health effects.”