U.S. clandestine drug labs are typically involved in the production of one or more amphetamine-type drugs, as well as such drugs as ecstasy or GHB; labs may also refine cocaine shipped in from other countries. Illegal labs have been found in city, suburban, and rural locations in such facilities as private residences, motel rooms, barns, garages, businesses, storage facilities, vacant buildings, and even vehicles. These operations tend to be unsophisticated, and product purity, safety, and protection of the environment are not important considerations. Although physical locations for labs may vary, they share a number of common identifying characteristics. Windows will be blacked out or boarded up from the inside, or blinds may be continually closed even in daytime. Bright lights may show through gaps in blocked windows, indicating ongoing activity especially late at night. Strange and unpleasant odors may come from the building. Hoses and pipes for ventilation and exhaust fumes may be observed sticking out from under windows or through holes in outside walls. Inside, labs are usually cluttered with trash, empty containers, and containers filled with hazardous waste. Chemicals used in most drug labs are highly toxic and volatile, making them vulnerable to fire or explosion. This poses significant danger to lab operators and to any law enforcement officers entering the lab. Even when called to investigate an apparent abandoned drug lab, dangers continue to exist from hazardous, toxic, and explosive wastes left by the operators.