"Bottom line is, we'll continue to fully cooperate with any investigation that goes on and own up to any mistakes and push forward and keep going", he said.
FEMA is already under scrutiny as the potentially devastating Hurricane Florence prepares to make landfall along the Carolina coast. "Doing something unethical is not in my DNA, it is not part of my track record", Long told reporters at a briefing on the storm.
Long, who has served in his position since June 2017, also reportedly drew the attention of DHS Secretary Kirstjen Nielsen for absences in the office, apparently due to his frequent travel home.
FEMA's James Joseph said even with all of its assets, there are limits to what it can do. "FEMA fully cooperates with all investigations conducted by the DHS OIG".
"Right now, that money has nothing to do with what you see behind us", Long said from FEMA's response center in Washington.
The inspector general is looking into whether taxpayers inappropriately footed the bill for Long's trips, according to the report, citing three unnamed sources.
Long reportedly began having a government driver take him home since he took control of FEMA previous year. "The Secretary is confident in the leadership at FEMA and their proven disaster management ability", DHS spokesman Tyler Houlton said in a statement to The Hill on Friday. Since his confirmation, the Administrator quickly earned the respect of the entire emergency management community, many in Congress and, most importantly, the FEMA workforce, during the most historic and challenging time in the agency's history.
Several current and former Trump administration officials have been investigated over their travel expenses. Health and Human Services Secretary Tom Price was sacked previous year after it was disclosed he took costly charter flights instead of commercial planes. Former EPA head Scott Pruitt, for example, was forced to resign over his travel habits.
Interior Secretary Ryan Zinke is now under investigation for his role in a real estate deal in his hometown.