(CNN) Scott Pruitt, the top federal official responsible for protecting the environment, is surrounded 24/7 by a cadre of agents because of the high number of threats against him.
The around-the-clock protection, described to CNN in recent months by federal officials, is an unprecedented level of security for the Environmental Protection Agency administrator. But the agency's inspector general's office said Pruitt, a controversial pick to lead the agency, is attracting an unusually large number of threats to his safety.
"We have at least four times -- four to five times the number of threats against Mr. Pruitt than we had against Ms. [Gina] McCarthy," said Patrick Sullivan, EPA's assistant inspector general for investigations, referring to Pruitt's predecessor during the Obama administration. He declined to provide the specific numbers of threats against Pruitt.
"They run the variety of direct death threats -- 'I'm going to put a bullet in your brain' -- to implied threats -- 'if you don't classify this particular chemical in this particular way, I'm going to hurt you,'" Sullivan told CNN in an interview. "Then there's implied threats -- like they say in New York, with the mafia: 'If you come after me and my family, I'll come after you and your family.'"
Sullivan's office is responsible for investigating the threats made against Pruitt.
The Washington Post first reported on Pruitt's security detail Wednesday.
CNN reached out to EPA for comment on this story but did not receive a response.
The EPA's Criminal Investigation Division is providing Pruitt's 24/7 security detail, a labor-intensive responsibility that has resulted in special agents being pulled from their regular posts investigating environmental crimes. These agents are armed federal law enforcement officers who typically investigate cases such as the dumping of hazardous waste, improper disposal of dangerous substances like asbestos, and pollution of drinking water. Some are former FBI agents.
The EPA's Inspector General's Office said it has been asked to investigate whether Pruitt's security detail is a proper use of environmental enforcement officers, and whether the practice detracts from the agency's mission of cracking down on environmental crimes. Citing its policy, the Inspector General's Office declined to say whether it was investigating the complaints.
No previous EPA chief has ever received a 24/7 security detail, the Inspector General's Office said.
McCarthy was accompanied by security personnel during the workday only, and occasionally on overseas travel.
Christine Todd Whitman, who held the role under President George W. Bush, told CNN she frequently "walked to work at the EPA by myself."
"I had no security at until after September 11, and that was only during travel," Whitman said.
Whitman criticized Pruitt's request for an expensive security detail while he also proposes deep cuts to the agency's budget.
"If he has had enough serious death threats, then he shouldn't have proposed the deep cuts to the EPA budget because he needs those people to go after the bad actors," she said in an interview. "What worries me is if these people are being used for protecting him, they are not cracking down on environmental crimes being committed by companies."
CLARIFICATION: This story has been updated with more of Whitman's comments to clarify her thinking about why Pruitt shouldn't have proposed cuts to the EPA budget.