Washington ? The food industry’s private inspection system failed to catch filthy conditions at a peanut company blamed for a nationwide salmonella outbreak because the firm itself hired the inspectors, lawmakers said Thursday.

The House Energy and Commerce investigations subcommittee released new documents that showed how private inspectors hired by Peanut Corp. of America failed to find long-standing sanitary problems at company facilities. Peanut Corp. is at the center of a nationwide outbreak that has sickened nearly 700 people and is being blamed for at least nine deaths.

“There is an obvious and inherent conflict of interest when an auditor works for the same supplier it is evaluating,” said Rep. Bart Stupak, D-Mich., chairman of the subcommittee. He termed it a “cozy relationship.”

Last summer, Peanut Corp.’s private inspector, a company called AIB, awarded the peanut processor a certificate in 2008 for “superior” quality at its Plainview, Texas, plant. This year, salmonella was discovered there.

The outbreak was initially traced to a Peanut Corp. company facility in Blakely, Ga. Later, contamination was found at the Texas plant. Peanut Corp. is under criminal investigation for allegedly shipping products it knew to be tainted.

Owner Stewart Parnell has refused to answer questions from lawmakers, citing constitutional protections against self-incrimination. On Thursday, Parnell told The Associated Press he couldn’t comment on the allegations and referred questions to his attorney, who was not immediately available.

Federal law does not require food companies to pay for their own inspections of suppliers. Nor are industry labs and inspectors required to tell the government about any problems they find.

At least one food company that used its own inspectors, Nestle USA, ultimately decided not to do business with Peanut Corp. Nestle USA had no recalls.

The committee released a 2002 Nestle USA inspection report of Peanut Corp.’s Blakely plant. “They found that the place was filthy,” said Rep. Henry Waxman, D-Calif.

Auditors found at least 50 mouse carcasses in and around the plant and also a dead pigeon “lying on the ground near the peanut-receiving door.”