More than a hundred people showed up to face the Environmental Protection Agency in Denver at Union Station on Wednesday — the only day the public could speak in person to the EPA about the agency's proposal to relax rules for how often oil and gas companies need to check for leaking gas.

The EPA said the proposal would change rules set in 2016 during President Barack Obama's administration.

"The proposal is to keep leak detection in place," said John Millett with the EPA. "But only require it less frequently. So moving from a more frequent monitoring to an annual basis for certain system and certain sizes.”

The proposal says that well sites that produce 15 barrels of oil and natural gas or less would be required to monitor for leaks once every other year. Sites that produce more than that would be required to check annually.

Throughout the day Wednesday, the EPA heard concerns ranging from health to the environment, including Maria Guerrero, a mother of two from Aurora, who came to testify.

"Instead of progressing we are going to be set back," she said.

Her concerns were mirrored by Amelia Meyers, a climate and clean energy advocate with Conservation Colorado.

"Some of those compounds are really harmful to our health," Meyers said. "Other pollutants are making the brown cloud worse."

Also in the EPA's proposal is the estimate that there is the potential for an additional 480,000 short tons of methane and 120,000 tons of volatile organic compounds to be released over a six-year period. The EPA said methane can create pollution when it reacts with the atmosphere.

Volatile organic compounds can be harmful for some people’s health at certain levels, according to Millett. Since this was the only public hearing in the country, people came in from Ohio, Pennsylvania and drove from New Mexico.

Millett said the EPA started considering the changes after being petitioned by oil and gas companies. The agency released their own press release saying the potential changes would align with President Donald Trump's energy agenda.

The idea is supported by Western Energy Alliance, a nonprofit trade association representing more than 300 companies in the western U.S.

Western Energy Alliance's president, Kathleen Sgamma, said any additional methane or volitale organic compounds released would be more than evened out because the oil and gas industry is also focusing on reducing greenhouse gas emissions.

She pointed towards data from the federal Energy Information Administration that tracked CO2 emission reductions from 2006 to 2017 as some companies shifted from coal to natural gas. The EPA confirmed Colorado has more stringent regulations when it comes to checking for gas leaks with or without any further changes.

Millett said those standards would continue even if the federal rules changed, so regulations for local companies wouldn’t change drastically. Sgamma said these changes could actually help companies be more efficient.

“It does mean Colorado producers don't have to do redundant inspections and not having to keep two books,” Sgamma said.

She also said regardless of any rule changes, their commitment to reduce methane gas emissions will stand. Meyers with Conservation Colorado argues "pollution doesn't know any physical boundaries. We need to make sure all of the air in the southwest is clean."

The public comment period continues through December 17. People can both read up on the proposal and submit their opinions online at this link.