The 911 call came into the Martin Police Department in Tennessee at the busiest time of day, when school was letting out and the roadways were choked with cars.

A mail carrier saw some white powder in a rural mailbox. Thinking it could be anthrax, he closed the lid and called the cops.

Though the postman was just being careful, that call took its toll on the tiny police force in the town of only 10,500. When the homeowner couldn't be reached, all seven officers on duty dressed in rubber containment suits and headed to the scene with a handful of firefighters.

The mailbox had to be taken apart. The area had to be cordoned off. Traffic had to be directed. A protective container to collect the substance had to be found. Then the homeowner pulled into the drive.

She told them the powder was pesticide.

"Another 30 minutes, and it would have been on its way to be tested," said Martin Public Safety Director J.D. Sanders. "We're not equipped for that sort of stuff. It takes a lot of our resources and a lot of time."

Police and fire departments around the country are struggling to cope with the torrent of calls coming in from people who think they've seen anthrax.

Because of limited resources, small-town forces often have the most trouble meeting the demands. More than 85 percent of police departments in this country serve communities of less than 25,000, Sanders said. And 80 percent of fire departments are volunteer, according to the International Association of Fire Chiefs.

"We want to be able to handle everything, but we don't have the funding or the staffing," said IAFC Executive Director Garry Briese. "Unfortunately, we are overstressing our resources right now."

On Tuesday alone, as news swirled that anthrax-contaminated letters had reached the offices of Sen. Tom Daschle, D-S.D., and ABC News, the IAFC documented 2,000 calls from people worried they'd come across some of the powdery toxin themselves. That's compared to zero anthrax-scare calls on a typical day in less panic-stricken times.

General protocol for authorities investigating a suspicious-substance report involves blockading the area, rerouting traffic and donning plastic gloves, masks and goggles — or rubber vapor-trapping suits if they have them — to try to figure out what the substance is. That can be difficult since many don't have experience with anthrax or hazardous materials. There are fewer than 1,000 hazmat teams in the U.S., Briese said.

If officials think the substance could be dangerous, they triple-bag it in plastic, place it in a special protective containment carrier and scrub down the surface where it was found. After they decontaminate themselves and anyone else exposed to the powder with water and soap or bleach, they send it off to the nearest public health department lab, which might be miles away.

The process can take hours.

"It's hard on small communities because they rely on volunteers," said Tom Halicki, executive director of the National Association of Towns and Townships. "In a situation such as we have now, [they spend] much more time responding to those calls and away from other work."

For that very reason, the police department in Carrollton, Texas — a Dallas suburb of 112,000 people — has a screening process for anthrax scares to assess whether there's a real threat before sending a crew to the scene.

That's helped for reports like the one that came in recently from a scared caller who thought anthrax was blowing around in the air, said Carrollton Police Chief David James. It turned out to be the stuffing from a toy that had been run over by a car.

In fact, all of the 20 or so anthrax-related calls his department has received in the last few days have turned out to be false alarms. Though James doesn't blame residents for being scared, the paranoia has stretched the force a little thin.

"It's interfering with our response to other items and with other preventive police work because we're responding to these little brush fires," James said. "People have become ultra-sensitive and don't know what to do."

He and Sanders offered the same advice to the panicky public: Continue to be cautious, but be reasonable and use good judgment before calling the authorities.

"This is so new and so frightening to people that they just overreact — in big cities, but here in the hinterland too," said Sanders. "We're not equipped to deal with that overreaction. We're telling folks here to use a little common sense."