Powder methamphetamine in foil. (U.S. Drug Enforcement Administration)

On Monday, police busted a suspected meth lab in a Howard County hotel room. In April, D.C. police raided a lab operating out of an apartment in the Northwest, the third meth bust in five months.

Wondering if your neighbors might be mixing up meth at home? The U.S. Drug Enforcement Administration offers some advice.

Meth lab indicators:

— The usual giveaway is a fire or explosion caused by the manufacturing process. The U.S. Department of Justice estimates that about 15 percent of meth labs are found this way.

— Strong, unusual odors similar to rotten eggs, cat urine, nail polish remover or ammonia.

— Unusually large amounts of cold medicine that lists ephedrine or pseudoephedrine as ingredients.

— Unusually large number of jars containing clear liquid with a white or red colored solid on the bottom, iodine, red phosphorus, fine red or purple powder, or dark shiny metallic purple crystals.

— Coffee filters containing a white pasty substance, a dark red sludge, or small amounts of shiny white crystals.

— Bottles labeled as containing sulfuric, muriatic or hydrochloric acid, or containers with rubber tubing attached.

— Glass cookware or frying pans with a powdery residue.

— Unusually large amount of camp fuel, paint thinner, acetone, starter fluid, Lye, drain cleaners, or lithium batteries.

— Soft silver or gray metallic ribbon stored in oil or kerosene.

— Propane tanks with fittings that have turned blue.

What to do if you find a meth lab:

— Do not touch anything.

— Do not turn on any electrical power switches or light switches.

— Do not turn off any electrical power switches or light switches.

— Do not eat or drink anything in or around the lab.

— Do not open or move containers.

— Do not smoke in or near the lab.

— Do not sniff anything.

— Decontaminate yourself and your clothing, and wash your hands and face thoroughly.

— Call the police or a DEA district office.