They worked hard, they played hard. 

Newly obtained emails reveal a seemingly close relationship, during and after work hours, between an EPA office and influential environmental groups -- showing a top agency official encouraged one such group to write an anti-coal report and even invited members to a summer bash featuring an “ice luge” for liquor shots.

The emails, originally turned over to a congressional committee and obtained by FoxNews.com, show communications to and from former EPA policy administrator Michael Goo, in the Office of Policy. While some deal with policy matters, others concern parties in 2011 and 2013 aptly named "Goofest." 

The parties, it would appear, were off the hook. 

Among the attendees to at least one of them was League of Conservation Voters official Tiernan Sittenfield, according to the emails. Goo emailed Sittenfield afterward to ask whether she had indeed attended, which she apparently had. 

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Goo, in his early 50s, replied: “How many shots of tequila had I had by then? Did you do a shot off the ice luge?”

An invitation to Sittenfield and others with the Natural Resources Defense Council for the 2013 party, Goo’s last before leaving the agency, also includes testimonials: “Even better than killing Bin Laden. I'm just jealous I don't have an ObamaFest -- Barack, 2012” and “Michael! Put your clothes back on! -- Everyone, Every Year.”

While the testimonials surely were satirical, the broader batch of emails nevertheless could raise serious concerns on Capitol Hill about his ties with the environmental groups.

In a May 6, 2011, email, Goo appears to share with Sierra Club’s John Coequyt internal EPA data on establishing emissions standards under the Clean Air Act.

Goo appears to suggest in a Dec. 9, 2011, email to Dave Hawkins, of the Natural Resources Defense Council, that his group produce material to help in EPA efforts to further regulate coal-fired plants.

“Let’s talk about this more … .Maybe a report or two in January showing that there is no new coal [plants] being built might be helpful,” he writes

Critics argue the emails don’t point to illegal activity but suggest that pro-environmental groups have undue influence on EPA policy. 

The emails came up Thursday during a House science committee hearing with EPA Administrator Gina McCarthy. 

Showing the emails, Rep. Bill Johnson, R-Ohio, said it appears Goo had a "close relationship with third-party groups," drawing particular attention to the coal report email and the party invites. 

"I have never been to a Goofest," McCarthy said, adding she is "aware" of them. She added, when asked if the emails show a "cozy" relationship: "I would agree that Michael Goo knows a lot of people ... I have no reason to believe that this was about influencing rulemaking." 

This is not the first time Goo and his actions have been subject to scrutiny.

The Energy and Environment Legal Institute acquired emails last year through a Freedom of Information Act request that appear to show the Sierra Club worked with the EPA to stop efforts to build the Keystone XL crude oil pipeline.

"Thanks so much for taking the time to meet with us on Keystone XL," the group’s Lena Moffit wrote Goo and two other senior EPA policy staffers in a Sept. 29, 2011, email. "Let me know if I can be helpful in any way -- particularly in further identifying those opportunities for EPA to engage that don't involve 'throwing your body across the tracks,' as Michael put it." 

Other communications appeared to show Goo arranged meetings with Coequyt at a Starbucks in Washington, D.C., which critics suggest was to discuss issues without having to sign into the nearby EPA headquarters. 

Goo worked for the EPA from 2011 to 2013, then joined the Energy Department in 2014.

In May of this year, the Republican-led House Committee on Science, Space and Technology sent the Energy Department a letter raising concerns that Goo might try to use text messages and personal email in an effort to avoid government transparency, as he had at the EPA.

The EPA did not directly address questions from FoxNews.com about the recent Goo emails. However, EPA spokeswoman Melissa Harrison said the agency is "committed to transparency and meeting its records-management obligations." 

And in an effort to meet that obligation, she said, the EPA in February updated its records policy to reflect new federal policy on personal email use.

"First and foremost, official agency business should be done on official EPA information systems," Harrison said.  

Goo, who worked for the Natural Resources Defense Council in the early 2000s before heading to Capitol Hill, has since left the Energy Department. He is now the legal counsel for Democrats on the House Energy and Commerce Committee.