Sen. Tom Carper of Delaware, the top Democrat on the Senate Environment and Public Works Committee, on Monday asked the Environmental Protection Agency's inspector general to investigate Administrator Scott Pruitt’s recent trip to Morocco to promote natural gas.

Carper says Pruitt’s four-day trip to Morocco this month was inappropriate because the EPA plays no formal role in overseeing natural gas exports, which falls under the jurisdiction of the Energy Department or Federal Energy Regulatory Commission.

The EPA inspector general already is investigating Pruitt for his use of private and military flights and his frequent travel as administrator to his home state of Oklahoma, where he served as attorney general. Carper wants the inspector general’s office to expand that probe to include Pruitt’s Morocco trip, which he says cost $40,000.

“I write to ask you to expand the scope of your current audit regarding Administrator Pruitt’s travel in light of his recent trip to Morocco,” Carper said in a letter. “This trip reportedly cost taxpayers $40,000, and one purpose of the trip was to promote U.S. liquefied natural gas exports. Specifically, I request that you review the purpose of Administrator Pruitt’s travels to determine whether his activities during each trip are in line with EPA’s mission ‘to protect human health and the environment.’”

The EPA says Pruitt traveled to Morocco to "update" environmental cooperation under the U.S.-Morocco Free Trade Agreement to include an option to import more natural gas from America.

The EPA said Pruitt's natural gas conversations in the North African kingdom came on the heels of discussions he led in the capital Rabat on sharing "U.S. best practices for solid waste management, public participation and crisis communication pursuant to the former Environmental Work Plan," which was established under the 2004 trade agreement.

After talking about LNG, Pruitt toured the IRESEN Green Energy Park, "where he saw firsthand the work being done to promote environmental innovation including solar energy across Morocco," the EPA said.

Morocco had been the head of the COP22 United Nations climate change talks last year and is a signatory to the 2015 Paris climate change accord.

Nevertheless, the country is making investments to begin importing LNG and start building natural gas-fired power plants. It still uses a lot of coal even as it transitions to more solar and is looking to diversify its fuel mix for electricity.

Morocco is a predominant importer of crude oil and other fuels, with little in the way of its own production capacity. It has examined the potential for hydraulic fracturing, but has turned to renewables to reduce its dependence on energy imports.