In order to be able to gauge the anticipated reductions in environment lead levels in Trail following start-up of the new lead smelter, a network of 35 homes was monitored from 1994 through 1998. This provided 3 years of data from prior to new smelter start-up and 19 months of data from after the transition. Average outdoor dustfall, street dust and indoor dustfall lead levels all dropped by about 50% after the new smelter went into operation. Soil lead concentrations in the yards of the 35 homes did not change significantly. The Sentinel Homes program also showed the home entrance mats can trap and hold large quantities of dust at the door and that indoor dustfall lead levels were significantly higher in homes that were being renovated.