WASHINGTON — Police cart off the evidence when they bust a methamphetamine lab, but the threat to the community does not leave with them.

Whether the lab was in a remote barn or house in a city, chemical residues from the manufacturing process can permeate rugs and float in the air. No law requires a cleanup before new occupants move in.

The U.S. House Committee on Science took another step to combat the growing methamphetamine problem earlier this month by holding a hearing on a proposed act that would look into how to clean up meth labs.

The Methamphetamine Remediation Research Act of 2005 would authorize research by the Environmental Protection Agency and the National Institute of Standards and Technology on how to best clean former meth labs and set guidelines on who should do it.

In 2004, 1,427 meth labs were uncovered in Iowa, up from 1,155 the year before, according to the Iowa Division of Narcotics Enforcement. Meth labs are often found in abandoned barns, houses, motel rooms and cars.

Dave Engelhardt, special agent in charge of the division, said there are no standards in Iowa for cleanup after a lab is discovered.

“We take care of the law-enforcement function. We seize all the chemicals associated with the production,” he said. “Then we are done.”

Rep. Bart Gordon, D-Tenn., the bill’s co-author, said comprehensive research has yet to be done on the health effects of methamphetamine residue on meth lab owners’ children, officers who collect evidence or future inhabitants.

But airborne particles are suspected of causing respiratory problems, and a witness at the Capitol Hill hearing suggested that one child’s cerebral palsy had been caused by extreme exposure to chemical residues in a meth lab.

“H.R. 798 is aimed at protecting innocent people whose lives are endangered by these illegal activities,” Gordon said at the hearing.

Ingredients of meth include ephedrine or pseudoephedrine, camp stove fuel, anhydrous ammonia, ether and lithium batteries.

After law enforcement officials collect evidence and dispose of the toxins, local governments handle the sites differently.

Engelhardt said that property owners, if they were not the ones producing meth, and Department of Public Health are notified. No state or federal laws mandate that an owner clear the property of residue, which can saturate carpets, insulation, soil and water.

Costs for an expert to determine what needs to be done range from $2,000 to $4,000, and cleanup can cost from $3,000 to $12,000.

Capt. Gary Foster, Story County chief deputy sheriff, said cost is a major reason there are no state or county mandates.

“We are not obligated to do anything because it is expensive,” he said.

Owners are not obligated, either. Engelhardt said law enforcement officials leave a placard on the premises saying that a methamphetamine lab was discovered and toxins may remain. An owner can decide to remove the sign without penalty, he said.

Engelhardt said owners sometimes merely touch up a property — painting over chemical burns, for example — before allowing new tenants or buyers in, leaving them at risk of exposure. The Iowa Real Estate Commission said owners must disclose all known conditions of a property, but if a new resident gets sick, the only options are a civil suit or moving out.

The Iowa Department of Public Health put together guidelines for cleaning properties, but it has no responsibility to inspect meth lab sites after they are discovered.

Kevin Teale, a department spokesman, said no reports have come in from new residents who have gotten sick after moving into a property.

Because discussion has just begun, the federal legislation doesn’t specify who should be responsible. The bill would provide money and information so legislatures can enact laws to fit the magnitude of their problems.

Engelhardt said he realizes the scope and complexity of the issue are taxing, but he said the process is necessary to keep people safe.

“A piece of property may be clean enough for 51-year-old Dave Engelhardt to live in, but not for someone with their two kids crawling around on the floor,” he said. “We would benefit from some standard being set for re-habitation.”