DENVER -- A federal jury has recommended that Dow Chemical Company and the former Rockwell International Corporation pay $553.9 million to thousands of property owners near the former Rocky Flats nuclear weapons plant.

Jurors found that residents near the plant suffered loss of property value and awarded nearly $177 million; they awarded an additional amount of nearly $177 million for property value loss due to nuisance; and they awarded punitive damages of $200 million.

Louise Roselle, an attorney for some of the plaintiffs, said the final award will likely be less because of limits in state and federal law, but could still reach $350 million after the judge reviews the verdict. The jury deliberated 17 days before reaching the verdict.

The class-action lawsuit was the largest in Colorado history and claimed the plant contaminated neighboring land, driving down property values for about 12,000 land owners. The now-defunct site northwest of Denver made plutonium triggers for nuclear warheads during the Cold War.

Rockwell, now known as Rockwell Automation, and Dow Chemical operated the plant at separate times under contract with the federal government.

In a statement, Dow officials said they will appeal, adding the judge improperly instructed the jury.

The lawsuit claimed the companies intentionally mishandled radioactive waste and then tried to cover it up. Defense attorney David Bernick said claims of a cover-up were wrongheaded and that contamination offsite was minuscule and didn't harm property values.

Attorneys have said the government would cover the damages and the companies' legal bills because they were operating as contractors.