As his convoy traveled over the causeway approaching New Orleans on Labor Day, Howard County firefighter Christopher L. Thompson could see only the broad expanse of Lake Pontchartrain. Then, as the city's skyline emerged, he spotted helicopters hovering above damaged high-rises. Entering the swamped city, Thompson's convoy passed by partially collapsed buildings, overturned trucks, blankets of debris and soldiers everywhere.

Finally, the convoy of trucks, trailers, utility vehicles and ambulances arrived in Gretna, La., a town of 18,000 just a couple of miles from New Orleans on the west bank of the Mississippi River. There, the rescue workers from Howard County and Baltimore found a ghost town, eerily quiet at midday amid the devastation wrought by Hurricane Katrina's savage winds.

The exhausted Gretna firefighters and police who met Thompson and his co-workers at a recreation center said the Maryland team was the first help to arrive since Katrina hit Aug. 29. No one from the Federal Emergency Management Administration had been there, Gretna officials said.

And so the Howard and Baltimore emergency workers began eight days of clearing debris, scouting for survivors, counting the dead and restoring order in the chaos all about them.

"I've been to a couple of tornadoes. I've been to several floods," said Thompson, 23, a Howard firefighter for four years. "You can't match it to anything. It's just the scale of it."

The 20 Howard firefighters, along with 110 rescue workers from Baltimore, volunteered for the assignment after Baltimore Mayor Martin O'Malley said he received a direct appeal from elected officials in Louisiana. The workers were part of a regional security task force -- including workers from Anne Arundel, Harford and Carroll counties -- that was organized after the Sept. 11, 2001, terror attacks. The 31-hour trip to Louisiana was its first deployment, Howard Fire Chief Joseph Herr said.

"I'm confident in the people we sent down there -- they're not strangers to each other. They've worked and trained with each other," Herr said.

The firefighters were scheduled to return home Tuesday evening. Support has poured out from Howard residents in response to the disaster that swept across the Gulf Coast. Schoolchildren and congregations have raised money. Residents donated blood and collected food and supplies. In addition, Howard's public school system has enrolled more than two dozen Gulf Coast students who evacuated their homes because of Katrina.

The rescue workers joined a Maryland contingent of about 600 civilians and military personnel who went to Louisiana and Mississippi, the first ones arriving the day after Katrina stormed ashore. The Maryland efforts came amid what many have described as a sluggish and inept response by federal authorities to the disaster.

Maryland National Guard units provided helicopter slings used by the U.S. Army Corps of Engineers to drop sandbags and shore up New Orleans's broken levees, said Katie Leahan, a spokeswoman for the Governor's Office of Homeland Security. About 200 Maryland doctors, nurses and emergency medical workers are staffing Operation Lifeline in Jefferson Parish, La., a project launched by parish President Aaron Broussard to get medical care to residents in mobile clinics at schools and fire stations.

"It's very hard to describe the magnitude" of the operation, said Clay Stamp, deputy director of the Maryland Institute for Emergency Medical Services Systems and a special adviser on Hurricane Katrina to Gov. Robert L. Ehrlich Jr. (R).

Stamp spoke by cell phone last week from an Anne Arundel mobile communications vehicle set up on the grounds of an evacuated hospital in Gretna. "We're building a [medical care] system," he said.

After spending several days there, Howard firefighters traveled by bus to St. Bernard Parish northeast of New Orleans, said Charles M. Sharpe, a battalion chief speaking on a satellite phone from a closed oil refinery in Chalmette, La. Unlike Gretna, which was spared severe flooding, St. Bernard Parish was inundated with a 22-foot storm surge, Sharpe said. The area also suffered a crude oil spill of 9,000 barrels, turning the standing floodwaters into a murky toxic soup. All of the parish's fire stations were destroyed or damaged, and Howard workers learned that much of the parish still hadn't been searched for survivors 10 days after the hurricane hit.

"That was difficult to accept," Sharpe said.

He and Capt. Gordon Wallace of the Howard unit directed the search operation in St. Bernard, coordinating the efforts of several hundred soldiers and emergency rescue workers from across the country and abroad. The Howard workers sectioned neighborhoods into grids and sent teams to hundreds, sometimes more than 1,000, buildings a day to search for survivors and check for hazardous conditions such as downed power lines and natural gas leaks.

"Once they got to work, the morale of the men improved," Sharpe said.

They evacuated some people, found others who refused to leave and discovered bodies. Private contractors were dispatched to recover the dead.

In the evening, the Howard and Baltimore workers returned to their base at the Gretna recreation center, which was powered by an electric generator. They stripped off their protective gear in a decontamination area, showered, ate, prepared for the next day and slept. As the days passed, rescue workers noticed fewer fires sending plumes of smoke into the sky. Gradually, more lights came on in the city at night, and more businesses reopened during the day. One night during dinner, the mayor of Gretna stopped by to say thanks.

Despite the hot and humid weather, Howard County members of a regional security task force wear heavy protective gear, which allows them to wade into foul floodwaters as they conduct searches house to house for survivors. Steve Bettis, on truck, loads cargo headed for Louisiana with the help of firefighters Timothy J. Daly and Duane Abbott, right, in Baltimore.Master firefighter Timothy J. Daly, left, and Lt. Stephen M. Hardesty survey houses and businesses in the New Orleans area.Howard officials keep daily logs of their work in St. Bernard Parish.Firefighters mark buildings in St. Bernard Parish to note their condition.