MEMPHIS, Tenn. - A tall man and a slender woman wiggled into their white hazardous-materials suits, putting on masks and gloves before venturing into the dark, two-story home where police say a methamphetamine lab recently exploded.

Gary Siebenschuh and a helper used a yellow photo ionization detector to measure for meth residue, maneuvering around debris and a hole in the roof caused by the Nov. 6 fire that injured a young child. They took wipe samples of walls, ducts, window sills, and other parts of the home, later sending them to a lab to be analyzed.

"The process is extremely cumbersome but I think it's necessary," said Dick Cochran, owner of the Memphis home where a renter was charged with making meth and causing the fire and explosion. He hired Siebenschuh to inspect the property.

"You don't know how bad a house can be contaminated," Cochran said.

Tens of thousands of houses have been used as meth labs the last decade and a cottage industry is developing around cleaning them up. Many Americans are more aware of the production of the highly addictive drug thanks to AMC's hit show Breaking Bad, which featured a high school chemistry teacher who turned into a meth cooker and dealer. In real life, cleanup contractors are the ones who deal with a property when a batch explodes or police raid an operation.

However, there is little oversight of the growing industry in most states, opening the door for potential malfeasance. And some homeowners are often reluctant to pay thousands of dollars to make a property safe, so many houses simply don't get cleaned for years, exposing residents and sometimes even neighbors to harmful chemicals.

Cochran expects to spend thousands to make the house rentable once again, with much of the cost covered by his insurance company. However, that is not the norm; many insurance policies do not cover meth cleanup.

To make a meth home safe, a certified contractor must remove and replace all contaminated materials, from walls to carpet to air-conditioning vents. Next, a certified "industrial hygienist" tests the home to gauge whether it can be lived in or needs more cleaning.

Hygienists and contractors find homes in different states of disrepair. Homes with no fires or explosions are easier to clean, but there is often a pungent odor, contaminated cooktops, carpets and walls, leaky roofs and dirty furniture. In the case of Cochran's home, Siebenschuh had to maneuver around scattered debris and a burned-out shell of a second floor and attic.

"You do testing in the front end, so we can find out how much meth is there," said Siebenschuh, whose company, G7 Environmental Services, also does testing for asbestos, mold and other contaminates. "Then the homeowner hires a contractor, and then he cleans it up."

Despite laws requiring landlords to disclose if meth had been made on a property, experts say such disclosures often don't happen and there are many people living in contaminated homes.

Exposure to meth residue can cause respiratory problems, and health officials say meth homes pose a threat to public safety. For example, squatters may enter abandoned homes, and children play around them.

Over the last decade, tens of thousands of homes have been used to cook meth, according to federal data. About 25 states have laws related to meth cleanup. Some states, such as Indiana, Kentucky, and Tennessee, place meth homes on quarantine lists. Some properties on Tennessee's list date to 2006, underscoring the years it often takes for some properties to be cleaned. Cleanup costs can range from $3,000 to $25,000, depending on the home's size and the amount of contamination.

Joe Mazzuca, CEO of operations for Meth Lab Cleanup L.L.C., said his business has been growing 30 percent annually in recent years. "We consider it to be still in its infancy," Mazzuca said.