WASHINGTON — The Environmental Protection Agency has been examining posts on Twitter and other social media about Scott Pruitt, the agency’s administrator, to justify his extraordinary and costly security measures, which have included first-class travel and full-time protection even on personal trips to Disneyland, the Rose Bowl and college basketball games, according to interviews and agency and congressional documents.

The social media efforts have come under scrutiny by some Democratic lawmakers, as well as senior officials at the E.P.A., who said the review had uncovered individuals sounding off against Mr. Pruitt but had found no actionable threats against him. One top E.P.A. official said in an interview that he had objected to the efforts when they were first discussed last year, to no avail.

Suspicious posts are referred to the E.P.A. inspector general’s office, which is charged with investigating threats. Spokesmen for both the inspector general and the E.P.A. declined to comment on the nature of specific threats, citing security concerns. The E.P.A. spokesman, Jahan Wilcox, said in a statement, “Scott Pruitt has faced an unprecedented amount of death threats against him.”

But two Democratic senators said on Tuesday that an agency whistle-blower had provided them with an internal E.P.A. memo concluding that a threat assessment prepared by Mr. Pruitt’s security detail did not appear to justify the increased protection. The internal memo was prepared in February by the intelligence unit of the agency’s homeland security office, according to the senators, Tom Carper of Delaware and Sheldon Whitehouse of Rhode Island.