TORONTO -- A ninth Ontario hospital is warning former patients about improperly sterilized equipment despite government assurances yesterday that sterilization procedures at the province's 154 hospitals are safe. Grand River Hospital in Kitchener said it is tracking down about 100 women who may have been exposed to human papilloma virus between May 1990 and November 2003.

A cryotherapy probe used in the treatment of a cervical condition was cleaned but not sterilized in accordance with Health Canada guidelines, Dr. Chris Steingart, Grand River's medical director of infection prevention and control, said in a statement yesterday.

The hospital said it is in the process of sorting through patients' files in an effort to contact each one.

The number of affected patients wasn't immediately clear because the sterilization procedure in question has been used since 1990 -- seven years before the hospital introduced its electronic patient registration system.

"We're confident that the number of women who may have had this procedure at Grand River Hospital in the last 13 years is less than 100, but we are committed to conducting the most thorough evaluation possible," Steingart said.

The announcement came on the same day Ontario Health Minister George Smitherman told a news conference provincewide audits have failed to turn up problems at other hospitals.

Smitherman ordered the audits last fall after eight hospitals across Ontario reported they had used improperly sterilized equipment.

A total of about 1,300 patients have been told to be tested for HIV and hepatitis because of potential exposures from improperly sterilized equipment.

At least two class-action suits have also been filed against some of the hospitals on behalf of the patients.