Washington ? The National Weather Service bought and installed defective equipment designed to keep power flowing to storm-detecting radar, then quietly replaced the problem system by paying the same contractor for replacements, government documents show.

An internal investigation has concluded Weather Service officials “seriously mishandled” the contract by paying for the failed units, rather than forcing the contractor to cover the costs as a government lawyer had repeatedly urged.

The probe also found officials bought the second set of equipment without considering competitive bidding, and made no mention of the decision to pay for defective equipment in official records, according to documents obtained by The Associated Press.

“How easy it was for a handful of people to violate established public policy for contracting,” said Robert Curtis, the Weather Service contracting specialist for the original contract and the settlement. During that process, Curtis complained to a top official that the settlement he was ordered to write would improperly pay the contractor for the defective equipment. Curtis then was fired; the reasons for his dismissal are in litigation.

The payments went to the prime contractor, Powerware Corp., of Raleigh, N.C.

Officials can’t agree on the government’s extra cost from the failures.

The inspector general of the Weather Service’s parent, the Commerce Department, said the amount was $4.5 million but the fired specialist, Curtis, alleges it was $18.5 million.