Public health officials urged pet owners to contact veterinarians, while many area veterinarians said they would provide free inoculations in response to yesterday's announcement that millions of dogs nationally might have received faulty vaccinations in the past two years.

The District will offer free rabies vaccination at several area schools each Sunday in October, said Tina Harper, chief of the D.C. Department of Human Services animal disease control division. "Anyone who has doubts or thinks their dog needs a new vaccine should come to the free clinics," she said.

"It can't hurt to have another vaccination, and we recommend it. The free shots are an ideal opportunity."

Dr. Candace Olson, clinic manager of Cherrydale Veterinary Clinic in Arlington, said vaccination certificates provided to pet owners indicate whether inoculations were manufactured by Norden Laboratories. However, the certificate does not specify how the vaccine was injected.

That information is critical because the Norden vaccine is considered effective only when it is injected into a muscle, the established method. The method of injecting it under the skin failed to meet federal standards, said Olson, whose clinic does not use the Norden vaccination products.

The D.C. Animal Shelter has used the newer subcutaneous method in injecting the Norden vaccine, which is considered less painful to the animal, Harper said.

Some local veterinarians, such as Dr. Margaret Janes, are writing letters to their clients whose dogs may be affected. Janes, president of Janes Veterinary Clinic at 520 Eighth St. SE, said she used the subcutaneous method until recently. She said she would administer the vaccinations again at no charge.

Company officials told Janes that they will reimburse her for the vaccinations, but she said it is unclear whether Norden will pick up her additional costs, including paper work and syringes.

"The dogs that are going to be in the worst shape are the ones who have had only one vaccination in the last two and a half to three years and almost due for another shot now," said Janes.