Arlington County's latest homeland security weapon is a mobile trailer that will stand ready to whisk off to any emergency and give stressed-out evacuees all the comforts of home: fresh water, medicine and plenty of . . . kitty litter.

County officials this week unveiled a mobile emergency pet shelter, a 20-foot trailer that will be stocked with food, animal crates and other supplies to create "pet-friendly" wings at local community centers and schools used as shelters during floods or other emergencies. The county purchased the trailer and contents with $20,000 in federal homeland security money.

Spurred by tales of owners forced to abandon their pets during Hurricane Katrina in 2005, jurisdictions around the region in recent months have begun wide-scale contingency planning that includes not only people but their furry pals. Fairfax County just shelled out $35,000 for an incident response center -- complete with air conditioning and its own generator -- for its animal control staff.

Montgomery County's animal control staff is trying to find warehouses or other buildings near 26 high schools, which have been designated as possible crisis shelters that could house pets. Dog-crazy Alexandria is raising money for its own pet trailer.

Since Katrina, the District has spent more than $100,000 stockpiling cages, leashes, medicine and other supplies needed for a portable shelter.

Fairfax is leading a year-long effort to create a regional animal disaster plan with a $200,000 homeland security grant, officials said.

"Katrina taught us a huge lesson. . . . People aren't going to evacuate if they can't take their pets," said Debbie Powers, a deputy coordinator in Arlington's office of emergency management. "Our policy has changed -- we'll do shelters for people and have pets right there in the same facility."

The pet trailer has nonetheless caused some yelps of protest from residents and activists, some of whom have said the purchase is a waste of money.

Arlington resident Christopher Bannon, 47, a software developer, said he was "shocked" to learn that the county was "spending homeland security money on pets. It doesn't seem to be the right priority."

"I'm a pet owner. I have a cat. But emergency money should be used for emergencies," Bannon said.

As much as he loves his cat Nile, a shelter rescue cat, he would hate to think Nile would squeeze out a child or other evacuee needing help, Bannon said.

The Department of Homeland Security approved the county's use of $20,000 of a $217,000 Urban Area Security Initiative grant for pet sheltering, Powers said. The county decided that the trailer was the best way to use the funds.

A DHS spokeswoman said that the grants go to 46 localities around the country to assist with emergency planning and that state and local officials have wide latitude for their use.

Robert Griffin, the county's director of emergency management, said Arlington just unveiled another mobile trailer for people, lest anybody get the idea that the county is neglecting humans. Now officials will be able to set up shelters in minutes during a crisis, instead of hours, they said.

Last year, Congress passed the Pets Evacuation and Transportation Standards Act, which mandates that localities have provisions for pets in their emergency plans. Work is underway for a regionwide pet disaster plan, which will look at public education and target locations for animal shelters, said Stephen Dickstein, the chief of public safety programs for the Metropolitan Washington Council of Governments.

Although the images of pets roaming loose after Katrina accelerated planning efforts, Fairfax County has made provisions at least since Hurricane Isabel in 2003, said Mike Lucas, chief animal control officer for the county. After flooding in the Huntington neighborhood last summer, the county cared for several dogs and cats -- and one hamster.

Montgomery also has a policy temporarily taking in pets brought to people-only shelters but, since Katrina, is looking to formalize its plan with "pet-friendly" centers next to area high schools that could be mobilized as shelters, said Paul Hibler, county's deputy director for animal services. When torrential rains threatened the dam at Lake Needwood last summer, a dozen evacuees with pets ended up finding last-minute refuge at the Montgomery County Fairgrounds.

Given such events, officials say it's only wise to plan.

"This is money well-spent, because you will lose human life if you don't address this problem. A lot of people won't leave if their animals can't go with them. . . . That's been shown time and time again," Dickstein said.