In April 2010, The Environmental Protection Agency(EPA) passed a Federal Law that requires that contractors who work on pre-1978 lead homes be certified and must perform a lead test to determine if any lead is present in previously painted surfaces if replacing 1 window or door, disturbing more than 20 square feet of the exterior or disturbing more than 6 square feet of any interior room. If the lead test is positive, only a Lead Safe Certified Firm can perform the work (currently only 20% of contractors are certified in California).