Stephen Lehtonen of the California PHCC says contractors should be wary of mold and not disturb it in any way. "There is the potential that a contractor can create a liability and we don't want that," said Lehtonen. The California PHCC is aiming to educate both contractors and the general public so they can recognize the potential for a mold problem.

Mold can be a problem in any area of the country, but it is especially common in areas that are humid or get a lot of rain and warm winters. Mold thrives in spaces that are damp and dark, such as basements, crawlspaces and under refrigerators. Leaky plumbing is a very common cause of mold because the leak moistens organic material (such as wood) within a building's walls or ceiling. This creates the perfect environment for mold. Drywall is another medium upon which mold thrives.

Mold can cause a number of fairly serious health problems that usually affect the respiratory system. But many times, the symptoms of mold irritation are identical to allergies. One particular type of mold, stachybotrys, was responsible for the deaths of 10 infants in Cleveland and is particularly dangerous. Stachybotrys causes bleeding of the lungs and is estimated to inhabit 5 percent of all houses in the nation. It is a black, slimy mold that will smear when touched and is capable of spreading airborne spores.

Today's energy-efficient houses are proving to be increasingly mold-prone, since many of them do not have adequate ventilation for controlling mold growth. Current laws for mold remediation are very loose, but that may change in the future - which could result in liability problems for contractors.