SANTA ANA, Calif. (AP) — An investigation finds claims of retaliation against whistleblowers in the Orange County Fire Authority over problems in hazardous-materials inspections are unsubstantiated.

The Orange County Register reports officials would not release details ofthe five-month probe, citing personnel issues.

But a statement released Monday said the outside investigator hired by the agency "did not support any of the allegations of retaliation brought against OCFA management."

The newspaper says three anonymous complaints made at the agency's fraud hotline earlier this year prompted the internal investigation and the hiring of an Encinitas law firm to look into the claims.

The claims contended that Fire Authority administrators retaliated against employees who reported mismanagement of a hazardous-material inspection program, which was found to have billed hundreds of businesses for inspections that were not made.