During the attacks on the World Trade Center, the Battery Park City man fled his apartment across from the twin towers and took refuge with his traumatized dog Sally on a barge docked at a nearby marina.

But Concister, who owns Le Pet Spa, a pet supply and grooming shop in lower Manhattan, realizes he was much luckier than most of the area's pet owners.

"Most people couldn't get to their animals for days," said Concister, 44, whose dog still shakes when she hears loud noises.

Since the recent upgrade of the country's terror alert, bags of kitty litter, cases of pet food and emergency kits have been flying off the shelves of his store on Rector St.

In the last two weeks, Concister has sold more self-replenishing water bowls and automatic feeders — which retail for as little as $8.99 and can dispense up to four days worth of pet food — than he has sold the entire winter.

"In anticipation of another tragedy, pet owners are making sure their animals will be taken care of," he said.

But the looming threats of bioterrorism and chemical attacks also weigh heavy on the minds of the city's pet owners. Two of Concister's customers said they recently purchased custom-made gas masks for their dogs.

Is the threat of bioterrorism a genuine concern for the city's pet owners?

"We think it is," said Gayle Brown, assistant director for the Center for Food Security and Public Health at Iowa State University's College of Veterinary Medicine. "Biological warfare doesn't necessarily have to be aimed at humans."

Brown said that while smallpox affects only humans, many poisons and diseases can affect both animals and humans and can be spread between species — including anthrax, botulism and plague.

Animals can be used as carriers for life-threatening diseases, Brown added, noting they sometimes can be infected without showing symptoms.

"It's important for people to know the risks and to know to keep an eye out for unusual behaviors or physical changes," Brown said.

The city Office of Emergency Management recommends making a plan to go somewhere that's safe for both pet and owner.

While shelters for people won't accept pets, people should call local animal shelters for guidance, suggested Sandra DeFeo, executive director of the New York Humane Society.

Animal shelters often have a huge foster network of people willing to take in pets, she said.

"The ultimate way to prepare is to practice ahead of time," DeFeo said. She suggests people practice their exit route, have a carrier ready by the exit, keep an extra supply of any pet medication and give keys to neighbors. She also suggests owners make provisions for pets in their wills, keep pets' vital information in their wallets, and place a sticker on the door indicating there are pets inside the home or apartment.