Jackson's boss, EPA administrator Scott Pruitt, is the target of more than 10 open investigations related to allegations he misused taxpayer funds and punished staff for raising concerns about his spending.
Most of the committee's six Democratic members have vehemently opposed Pruitt's efforts to roll back climate and pollution regulations introduced under Democratic former President Barack Obama, and have seized on the controversies around Pruitt's conduct to call for his resignation. Tom Udall (D-N.M.), the top Democrat on the committee, told Pruitt in the hearing.
EPA chief Scott Pruitt is denying that a member of his press staff sought to plant negative media reports about Interior Secretary Ryan Zinke in the hopes of deflecting attention from Pruitt's problems.
A House committee and the Government Accountability Office also are investigating Pruitt.
Udall is citing an email written by EPA's security chief saying Pruitt "encourages the use" of emergency lights. Lisa Murkowski, who heads a Senate Appropriations subcommittee, told Pruitt at a hearing normally expected to focus on budget matters.
According to EPA's inspector general, Pruitt had himself asked for the security, which was given to him.
"No, I don't recall that", said Pruitt, when asked if he had personally requested the use of lights and sirens.
Despite the mounting investigations, Trump has said he supports Pruitt.
At one of the House hearings last month, Pruitt spoke broadly of taking responsibility for changes at his agency, and said he had "made changes" in his practice of first- and business-class travel.
"I am concerned that numerous important policy efforts that you are engaged in are being overshadowed because of a series of issues related to you and your management of the agency", she said. Cindy Hyde-Smith (R-Miss) said she was "most impressed" with his push to ease regulations and clean up a contaminated site in her state.
Elkins Jr. said the decision was made by the agency's Office of Criminal Enforcement, Forensics and Training after being informed that Pruitt had requested that such protection begin once he was confirmed as administrator.
Grassley has asked the EPA to cease issuing the Renewable Fuel Standards (RFS) waivers to the refineries.
"Then that's a gift, that's a violation of federal law", Udall said, noting that subordinates of federal officials are prohibited from providing free services to their bosses.
The study would show that the chemicals - known as PFOA and PFOS - are unsafe to humans in much smaller quantities than the Environmental Protection Agency has previously said, Politico reported this week.
Pruitt was also criticized for a tweet on April 13 by the EPA's official account that cheered Senate approval of former coal lobbyist Andrew Wheeler as deputy administrator of the EPA and stated that "the Democrats couldn't block the confirmation".
In his second round of questioning, Van Hollen tried again, reading directly from the IG report, which contradicts Pruitt's claim that he was not involved in the decision to provide such an unprecedented level of security for an EPA administrator.