The U.S. Mine Safety and Health Administration forwarded Monday its final report on the Wilberg Mine disaster to the U.S. attorney's office in Salt Lake City for possible criminal prosecution.

However, MSHA officials would not say if they recommended for or against prosecution, an agency spokesman in Washington said.The Dec. 19, 1984 Wilberg fire in Emery County killed 27 miners. MSHA, after extensive investigations within the agency and by committees of Congress, ruled that the accident was caused by a compressor that managers did not repair or replace even after it was known to be in operating unsafely.

MSHA said that compressor was allowed to run unattended in an non-fireproofed area until it overheated and caught fire. The agency said a partially blocked escape passage contributed to the deaths.

The United Mine Workers of America disputed the MSHA report, saying its investigation indicated the fire began on an overburdened conveyor belt.

MSHA had issued 34 citations against mine owner Utah Power & Light Co. and Emery Mining Corp., which operated the mine at the time of the deadly blaze.

The agency ordered the companies to pay $11,470 in fines, the largest penalty it had ever assessed for safety breaches. But an administrative law judge ruled in March that UP&L was not liable for the fines because it was not the mine operator at the time.