EPA Administrator Scott Pruitt at the Western Conservative Summit.

Grace Hood/CPR News

EPA Administrator Scott Pruitt highlighted his agency's work to a friendly audience at the Western Conservative Summit in Denver on Friday night.

Speaking to hundreds, Pruitt talked about his agency’s work at the Gold King Mine and the country's other Superfund sites, stating that the sites are getting cleaned up quickly.

The Associated Press reports that the EPA has delayed a report on the human health risks of wastewater draining from southwestern Colorado mines -- including Gold King.

The agency said Friday it will collect more data and do more analysis after local health officials, toxicologists and others reviewed an early draft. The study was expected this spring, but the agency now says it will be fall.

The study is a step in developing a cleanup plan for the Bonita Peak Mining District Superfund project, which includes includes 48 mining-related sites near Silverton.

One of those is the Gold King mine, where the EPA inadvertently triggered a spill of 3 million gallons of wastewater in 2015.

Pruitt also underscored recent methane and air regulation rollbacks he called too restrictive.

"Air quality issues on the West Coast are different than the southeast. We must as an agency embody that partnership, that federalism concept, to make sure we advance these principles. So we have given a rebirth to rule of law, a rebirth to process, and we've renewed our focus,” said Pruitt.

Key applause lines during Pruitt’s speech hit on returning rights to states. Pruitt said that the Obama administration dictated too much policy from Washington D.C.

“We’re going to engage in true federalism and partnering together to improve air quality and water quality,” said Pruitt. “A one-size-fits-all strategy with respect to these issues does not work.”

The message of state’s rights resonated with Susie Guerra from Lakewood.

“It’s nice to know that we have someone who’s considering taking care of individuals and keeping our lands free for individuals to use. We’re so happy for that,” she said.

Pruitt has been under close scrutiny for his spending and relationships with industry representatives. There are currently about a dozen federal inquiries into his spending and management. And on Friday, House Democrats formally requested that the Justice Department investigate Pruitt for potential criminal conduct.

In a letter to FBI Director Chris Wray and Justice criminal division chief John Cronan, six Democratic lawmakers with oversight of Pruitt's agency allege he repeatedly violated federal anti-corruption laws by seeking to leverage his government position for personal gain.

“I knew that it was going to be noisy and competitive,” Pruitt said to the crowd, giving a nod to his critics. “In the midst of all that, the greatest response is to keep going. Keep advancing, keep persevering.”

Overall the message resonated with the outside-the-beltway conservative crowd, including Western Wire Opinion Editor Matt Dempsey.

“Frankly with all the noise in Washington D.C. right now you’re not hearing the policy side of what Pruitt is doing in Washington. You’re hearing about the noise,” said Dempsey. “Getting outside the beltway he’s able to convey that message in a much more aggressive way than what he’s able to do in D.C.”

The Associated Press contributed to this report.