MINOT, N.D. -- Tom Lundeen and his family must wait to discover if they are in mental and physical danger. For now, they'll settle for a home-cooked meal and a comfortable couch.

A wire service reports that the Lundeen family is among 20 still waiting to return to their homes near the site of a Jan. 18 train derailment that sent a cloud of anhydrous ammonia drifting over Minot. The toxic farm fertilizer killed one man and injured hundreds more.

Experts who have studied the physical effects of anhydrous ammonia and the emotional aspects of surviving a disaster say the lives of many will forever be changed.

"You can't even think about anything else other than the fact that we have our lives totally disrupted," Lundeen said, from his hotel room. "Your whole life is just turned upside down."

The cause of the crash may not be determined for months. Federal officials have been studying a section of rail that was replaced 18 months ago.

Canadian Pacific Railway spokesman John Bergene said the railroad has been focusing on helping Minot's 36,000 residents with expenses in the immediate aftermath of the derailment.

"We really have no idea what the numbers of people might be who will have some medical ill effects from this," he said. Mental health and other issues "need to be covered" at some point, he said.

At least one lawsuit has been filed against the railroad. Others are being considered.

Lundeen, his wife, Nan, and two teen-age children were sleeping Jan. 18 when they were awakened by what they thought was a plane crash. Within minutes, they could smell the ammonia, and then the cloud "just engulfed us," Tom Lundeen said.

The Lundeens went to the basement of their house, which is about 350 yards from the railroad tracks, and waited to be rescued. It took nearly four hours.

The family now tries to maintain a normal routine living out of a hotel room, but it is not easy. Offers from friends of home-cooked meals are a luxury.

"We're actually catching ourselves calling it home," Lundeen said. "It's a hotel. It's not the same."

Jim Semerad, a manager with the state Health Department's air quality division, said air monitoring at the derailment site likely will continue for weeks. Water monitoring might go on for months, especially near wells, he said.

Preliminary tests show no contamination of area drinking water wells or liquid water in the nearby Souris River, although more than 20,000 square feet of ice is being removed, health officials said.

About 43,000 tons of dirt have been trucked out already, but the scent of ammonia lingers in the air. About 7,000 tons of dirt remains to be hauled away.

Most of the workers who remain at the site are contractors, hired by the railroad after the emergency status of the cleanup waned, said Darcie Park, a railroad spokeswoman. They work near the track, just a few hundred yards from a road.

A few yards away sit dozens of large bags of a white powdery material used to suppress anhydrous ammonia fumes, which can be easily stirred up by the large earthmoving equipment.

After all the contaminated soil near the tracks is removed, the railroad must deal with anhydrous that soaked into the ground under the tracks during the 300,000-gallon spill.

Justin Meyer, an environmental engineer with the railroad, said the railroad will have to find some way to remove it other than digging out the soil and undermining the rails.

The number of people working at the site has dropped from 60 to about 30, Park says. Officials investigating the cause of the crash have long since wrapped up their onsite work, and most railroad hazardous materials officials also have left. But much work remains.

Phillip Goad and his crew of a dozen people will be sticking around. Goad is president of the Little Rock, Ark.-based Center for Toxicology and Environmental Health, which is helping health officials monitor air quality at the crash site and around the city, 100 miles north of Bismarck.

"We'll be here until it's done," Goad said. "Or until there aren't any vapors coming off that are bothering people, we'll be here."

Officials estimate that the earliest the 20 families will be able to return to their homes is Feb. 20.

Lundeen said Minot residents are preparing themselves for a long battle, though they are not even sure yet what they might be fighting.

"Everybody is very nervous about wanting to get the answers and not knowing if we're ever going to get them, about how this is going to affect our futures," he said.