The Agriculture Department's mad cow disease testing lab, located in a strip mall in Ames, Iowa, is not secure enough for storage of mad cow tissue samples, a USDA investigative report said.

The facility, part of the department's Animal and Plant Health Inspection Service (search), is close to other businesses and has limited security at its entrances and exits, said the report by the Inspector General's office, a part of USDA which conducts independent investigations.

APHIS officials had stated that "all pathogens of consequence had been removed," but investigators learned later from a laboratory official that a mad cow tissue sample remained, the report said.

The Ames facility diagnosed America's only known case of mad cow, in a Washington state Holstein, in December.

Officials of APHIS said the tissue samples posed little risk, but agreed they should not be in the strip mall facility and had them removed, the report said. Staffers have been told not to leave mad cow tissue samples at the site, it said.

The facility is to be relocated as part of a renovation of APHIS' National Centers for Animal Health (search), which is under way. The Bush administration's proposed 2005 budget has $178 million to complete the job.

Mad cow, also known as bovine spongiform encephalopathy (search), or BSE, is transmitted when animals eat feed containing BSE's infectious protein. Since 1997, the federal government has been strengthening measures designed to keep the protein out of feed.