A federal jury Wednesday awarded an environmental cleanup firm $84 million in a contract dispute with Monsanto Co. and other companies that dumped hazardous wastes at the Motco Superfund site in La Marque.

The Houston jury decided St. Louis-based Monsanto and the other companies breached their contract with and defrauded International Technology Corp. of Torrance, Calif.

The jury awarded International Technology $52.8 million in compensatory damages and $28.5 million in punitive damages, as well as $2.3 million in attorneys fees. The company was represented by Dan Davis, an attorney with the Dallas firm of Gardere & Wynne.

"We are outraged by the verdict and will pursue all possible avenues of appeal," Thomas Bistline, Monsanto's assistant general counsel, said in a prepared statement.

Monsanto will ask Judge Lee Rosenthal to set aside the verdict. If that fails, the company plans to appeal.

The Motco site consists of 11 acres were Monsanto and 21 other companies are known to have dumped hazardous wastes in seven pits.

The Environmental Protection Agency says styrene tars, copper, mercuric chloride, mercury and lead are known to have been dumped at the site. Motco was placed on the list of Superfund sites, among the federal government's top priorities for environmental cleanup.

Monsanto was the largest user of the site, dumping hazardous materials there intermittently from 1959 until the mid-1970's, company officials said.

International Technology was hired in 1988 by Monsanto and the other companies known as the Motco Trust to destroy wastes at the site using two portable incinerators. International Technology was to b e paid $30 million for the work.

But soon after the environmental cleanup firm began work at the site, it realized the job was far tougher than expected, making the $30 million price tag inadequate to complete the work, International Technology contended.

The chemical makeup, quantifies and mixture of wastes at the site were different from what International Technology said it had been told when it bid to do the work. International Technology argued. The Motco Trust also dumped an additional 1.4 million gallons of con-taminated water and wastes from another project into the Motco pits, the company claimed.

The parties began renegotiating the contract, and Monsanto told International Technology it was going to ask the EPA to approve another method to clean up the site, International Technology said.

On Dec. 4, 1991, International Technology halted the clean up of the site and filed suit., claiming breach of contract, fraud and negligent misrepresentation. Three weeks later, Monsanto and the other companies countersued, claiming breach of contract and fraud.

The Motco Trust developed its alternative plan, transporting the hazardous materials to another location for incineration. That program is still under way and is expected to be completed next year.

The case went to trial in the U.S. District Court for the Southern District of Texas on March 22. The jury ruled Monday morning in favor of International Technology.

Monsanto officials responded that they don't think the facts supported the verdict, noting: "We believe the facts showed that International Technology signed a fixed-price contract and then walked off the job without completing the work they signed up to do," Monsanto's Bistline said. "It's unfortunate that the jury didn't enforce the agreement."