OTTAWA - A judge on Monday acquitted four doctors and a US pharmaceutical company who were accused of negligence in the distribution of blood contaminated with HIV in Canada's worst health scandal.

It was the first criminal trial in the case, in which more than 20,000 people contracted human immunodeficiency virus and hepatitis C in the 1980s and 1990s. At least 3,000 people died, including 800 from AIDS.

The Ontario Superior Court in Toronto ruled that doctor Roger Perrault, the former head of the Canadian Red Cross, was not negligent in the case.

Two other Canadian doctors, an executive of Armour Pharmaceuticals, and the US firm itself were also acquitted.

They were accused of failing to detect infected blood samples and faced up to 10 years in prison if convicted.

The trial was over the contamination of seven children suffering from hemophilia, a bleeding disorder. They contracted HIV after taking Factorate, a product made by Armour Pharmaceuticals to help clot patients' blood.

In a 66-page decision, the judge said there had been "no conduct that showed wanton and reckless disregard. There was no marked departure from the standard of a reasonable person.

"On the contrary, the conduct examined in detail for over one and a half years confirms reasonable, responsible and professional actions and responses during a difficult time.

"The allegations or criminal conduct on the part of these men and this corporation were not only unsupported by the evidence, they were disproved."

But representatives and family members of the victims could not contain their anger at the verdict.

"It's a shock," said John Plater of the Canadian Hemophilia Society.

"I think every tainted blood victim is going to feel that there's no closure here as we feel it's been a miscarriage of justice," he said.

"The people who were at the core of this case were tested and were found to be HIV negative. They used this product and they became HIV positive. And these individuals were responsible for allowing that to happen."

Eddie Greenspan, a lawyer who represented the physician Perrault, said his client had done nothing wrong.

"We have always believed in Dr. Perrault's innocence ... Today's absolute vindication and his complete exoneration is something we've been hoping for and actually expected for the last 10 years, and now it has come.

The doctors face another trial over accusations that they did not take the necessary measures to stop HIV-positive people from giving blood and that they failed to inform the public about the danger.

The Canadian government announced last year it would give one billion Canadian dollars to victims who had not been taken into account in a previous agreement.