Democrats are pressing Environmental Protection Agency Administrator Scott Pruitt over his use of business-class flights to conduct agency business.

“Americans deserve an EPA administrator more dedicated to first-class protection of human health and the environment than to luxury travel at taxpayer expense,” Rep. Frank Pallone of New Jersey, the top Democrat on the House Energy and Commerce Committee, with other Democrats on the committee, wrote in a letter to Pruitt sent Tuesday.

Pallone wants Pruitt to clarify details on his use of business and first-class travel.

“To date, your agency has failed to provide a clear explanation as to whether your travel since becoming administrator complies with all applicable federal regulations and agency procedures,” the letter stated.

Pruitt was seen last week seated in business class while on a flight from Washington to Boston after the administration had proposed slashing the agency's budget by more than 20 percent, the Democrats pointed out.

Pruitt said he needs to travel first class for security reasons, as he has been threatened when seated in coach. But the Democrats don't believe it.

“It remains unclear how any possible security threats warranted the frequent issuance of waivers authorizing you to fly first-class on domestic flights, or how sitting in a first-class seat is safer than sitting in economy class,” they wrote.