Updated

The ranking member of the Senate Finance Committee launched an inquiry Tuesday into reports that National Science Foundation officials are using government computers to view pornographic Web sites during working hours.

In a letter sent to the NSF's inspector general Tuesday, Chuck Grassley requested access to all documents related to the "numerous reports" and seven investigations into "Abuse of NSF IT Resources" -- which are referenced in the agency's 68-page semi-annual report.

In one instance, the report cites an NSF "senior official" who allegedly spent 20 percent of his work hours "viewing sexually explicit" Web sites -- amounting to a potential loss of $58,000 in employee compensation.

Grassley has asked the NSF to disclose all "specific reports of investigations, audit reports, evaluations and information supporting the examination of the NSF network drive" by Thursday to "ensure that NSF properly fulfills its mission to strengthen scientific and engineering research, and makes responsible use of the public funding provided for these research disciplines."

"The semi-annual report raises real questions about how the National Science Foundation manages its resources, and Congress ought to demand a full accounting before it gives the agency another $3 billion in the stimulus bill," Grassley said in the letter obtained by FOX News.

Sen. Barbara Mikulski, who heads a subcommittee that doles out taxpayer dollars to the NSF, will work with Grassley on the probe, her spokeswoman told FOX News.

In response to Grassley's inquiry, the NSF released a statement Wednesday, saying the agency has a "long-standing policy prohibiting the inappropriate use of government IT resources -- including the viewing, downloading, or playing of sexually explicit material."

"Any NSF employee who violates the proper IT use policies faces immediate disciplinary action that can result in firing and civil or criminal penalties," Jeff Nesbit, NSF director of legislative and public affairs, said in a statement.

Nesbit said the "senior official" named in the report retired after receiving a final decision to remove him from federal service.

Click here to read Chuck Grassley's letter.