David Marcelli and Barney
Photo: David Sharpe David Marcelli and Barney

"Seek." That's the only command mold investigator David Marcelli of Westminster, Md., has to give his two best inspectors to set them off in search of mold. That's right, his best searchers are dogs.

Barney, a 3-year-old, 75-pound chocolate lab/pointer, and Sam, a 2-year-old, 70-pound black lab/bloodhound, have both undergone intensive training–the same kind a bomb- or drug-sniffing dog would go through–to learn to find mold in houses and commercial buildings. They're so good that they not only can find the microbial growth, they can tell Marcelli where it starts and stops within a few inches. And, while Marcelli uses all the tools of a mold investigator's trade (moisture meters, air samplers, etc.), Barney and Sam find the mold that often eludes the machines and people trying to sniff it out. After one mold investigator gave up a search in a 750,000-square-foot federal building in Washington, D.C., Marcelli and his dogs were called in. Barney found it right away.

Marcelli points out that dogs' noses can detect mold in "the parts per billion," so it really has nowhere to hide. "They can smell under your carpet, behind walls, and through flooring." But, he adds, "unlike a moisture meter, Barney and Sam are living, breathing critters and there's a bond between us."

Both dogs are recertified every 90 days by the Florida Canine Academy, where each pooch underwent 1,000 hours of training before being sent to Marcelli, one of about 80 mold investigators in the U.S. using dogs for this work.

"They're wonderful problem solvers," Marcelli says. And they're great workers: "Instead of being greeted in the morning by a griping employee, I get a wet nose and a companion who actually wants to be there."

–Mark Clement