More than half of the $946 million in disaster relief appropriated by Congress after Mount St. Helens erupted in 1980 was spent for other purposes, the General Accounting Office has found.

The GAO, in a report released this week, said that six of the 12 agencies that received emergency funds in the wake of the Washington State eruption overestimated their needs by about $560 million. Five of them ended up diverting the surplus funds to other activities.

The largest surplus was held by the Small Business Administration, which spent only $66 million of its $430 million appropriation on activities associated with the disaster. Only the Education Department returned its excess appropriation to the Treasury.

Five other agencies ran out of money before they had completed recovery work, the GAO said, including the U.S. Corps of Engineers, which has already spent $60 million more than its $215 million appropriation on work associated with volcano cleanup.

The GAO told Congress that none of the agencies acted illegally, but that the situation pointed up a need for some changes in the way emergency disaster relief funds are appropriated and distributed.

"Because the appropriations act did not restrict the use of funds to Mount St. Helens work, agencies were free to use Mount St. Helens relief funds for other disasters or purposes," the investigative agency said.

The GAO recommended that Congress be a little more specific about how it intends relief funds to be used, or at the least designate a "lead agency" -- possibly the Federal Emergency Management Agency -- to coordinate the use of funds and redistribute some of the money if necessary.