The Consumer Product Safety Commission is about to lose $500,000 to $600,000, thanks to an error by agency officials.

The amount, which was appropriated to the agency for fiscal 1985, will have to be returned to the Treasury because the CPSC's principal budget officer was unaware of an amendment last year that prevents the agency from transferring unused salary funds to other agency activities, unless the transfer has been authorized by legislation.

"I was informed of this change late on Aug. 30 by a staff member on the House Appropriations subcommittee," wrote principal budget officer Thomas W. Murr Jr. in a memo to Leonard DeFiore, the CPSC's executive director.

"I have spent a great deal of time since then trying to learn the reasons for the change, if there are any exceptions or routes of appeal," Murr wrote. "At this point, it appears that there is no way to reprogram these funds and as a result, I anticipate a lapse of approximately $500,000-$600,000 in salary funds."

"This is a big chunk for our agency," said a commission source who asked not to be identified. The commission's budget for fiscal 1985 is $36 million.

Under the provision, which was part of last year's appropriation bill for the Housing and Urban Development Department and the independent agencies, legislation must be passed before salary funds can be reprogrammed; in the past, the approval of the Appropriations Committees was all that was required.

About $200,000 was unspent because the commission seat vacated by Nancy Harvey Steorts has not been filled. The amount would cover the salary of a commission member and three staff members, a CPSC official said.

In addition, the agency has not filled some vacancies in anticipation of a personnel ceiling that will take effect in fiscal 1986. Then the agency will have 568 positions instead of 587. One of the agency's most important positions, the director of health sciences, has been vacant since last fall.

SIZING UP THE COMMISSION . . . The House Energy and Commerce subcommittee on health and the environment has dropped a clause in the CPSC reauthorization bill that would have reduced the size of the commission from five members to three.

The bill, which was reported out of subcommittee last week by a 10-to-5 vote, had been delayed for some time because Rep. Henry A. Waxman (D-Calif.) was unable to muster a quorum to mark it up.

The controversial clause was eliminated after a compromise was worked out with Republican members to get the bill out of subcommittee. An additional clause was dropped that would have made it easier for the agency to disclose information about safety concerns that identified manufacturers or product names.

The bill would give the commission some authority to regulate rides in permanent amusement parks, establish a permissible minimum number of commission employes and authorize $37 million for the agency in fiscal 1986, $38 million in fiscal 1987 and $39 million in fiscal 1989 for the agency.

MORE ON ATVs . . . Although the CPSC has spent most of its time lately investigating the safety problems related to all-terrain vehicles (ATVs), the agency doesn't plan to take action until at least next summer.

"Tragically, nothing will be done for a year unless the commission addresses the issue head on, or the risk becomes intolerable to the American public and consumers demand action sooner," Commissioner Stuart M. Statler said.

The agency has been holding public hearings around the country to examine the safety risks associated with the motorized three-wheel, tricycle-like vehicles designed for off-road use.

At least 233 people have died in accidents involving ATVs from 1982 through June 20, 1985, the commission said; and at least 150,000 more have had to visit hospital emergency rooms. Nearly one-fourth of the injuries involved children under 12, and 50 percent of the accidents involved people under 16.

"I am concerned that the commission not wait until the body count is of such staggering proportions until it decides to take action to protect the American public," Statler said.

At the same time, Rep. Larry E. Craig (R-Idaho) has called on Statler to resign from the commission's investigation, saying he had prejudged the issue. In particular, the member attacked what he called Statler's dissemination of "personal press releases in the guise of 'fact sheets' under commission letterhead."

Statler said he will prepare "an extensive response" to Craig this week, which he said will "address the congressman's egregious inaccuracies."