The Labor Department proposed maximum allowable fines totaling $108,300 against three construction firms it cited for safety violations at a power plant in West Virginia where scaffolding collapsed six weeks ago, killing 51 workers.

The department also said the case is being reviewed for possible criminal prosecution and further civil action.

If violations alleged in the citations had not been made, "this tragedy would never have occured," said Occupational Safety and Health Administrator Eula Bingham in announcing the results of OSHA's probe into the disaster.

On April 27, the scaffolding peeled off a 400-foot cooling tower under construction for the Monongahela Power Co. at Willow Island, W. Va., plummeting the workers 170 feet to their deaths.

OSHA cited the tower construction company, Research-Cottrell Inc. of Bound Brook. N.J. with a total of 16 violations - 10 of them "willful" - and proposed fines amounting to $105,100.

It also cited United Engineers and Constructors Inc., the general engineering contractor, and Pittsburgh Testing Laboratory, which handled concrete testing for the project, for two serious violations each and proposed fines of $1,600 against each of the firms. That would bring the total to $108,300.

Willful violations differ from serious ones in that an employer is found to be consciously aware of violating the law or is aware of a hazardous condition and makes no reasonable effort to correct it, according to OSHA's regulations.

The law provides for criminal as well as civil sanctions when a willful violation results in death. Only Research Cottrell was cited for willful violations. A spokesman for the New Jersey firm said the company would not comment until it received a copy of OSHA's allegations and report.

Bingham told reporters yesterday the Labor Department, the parent agency for OSHA, is considering whether to recommend that the Justice Department undertake criminal prosecution. She said a decision has not yet been made.

Criminal penalties for violations of OSHA laws include fines of up to $10,000 and imprisonment for up to six months.

In the case of yeaterday's civil citations, the firms may either pay the penalty or appeal to the Occupational Safety and Health Review Board and the courts.

The proposed fines were among the largest levied by OSHA since its creaction eight years ago, officials said.

In its report, OSHA said there were "at least three interdependent factors" contributing to the collapse, specifically:

Failure to test whether the concrete that was being poured had cured sufficiently before the supporting forms were removed.

Inability of the scaffolding to resist loads because some necessary bolts were not used.

Failure to anchor and maintain the beam sections supporting the concrete lifting system so it could hold the loads that were being lifted.

Responding to criticism from the Health Research Group that earlier warnings by OSHA officials of scaffolding problems on a previously built tower should have prompted the agency to watch the project more closely, Bingham said the defects that caused the disaster might not have been apparent on any single prior inspection.

She said OSHA "makes as many inspections as we have the resources to do," although she acknowledged they may not be as frequent "as is appropriate for a hazardous industry."

Sidney M. Wolfe. director of the group, said OSHA's report tends to comfirm that a thorough inspection triggered by the earlier problems might have turned up the hazard that led to the April disaster.