Indoor air mercury concentrations following application of interior latex paint

Mercury vapors are released from paint containing mercury compounds used to prolong the shelf-life of interior latex paint. To determine whether homes recently painted with paint containing mercury had elevated indoor-air mercury concentrations, we studied 37 Ohio homes. Twenty-one homes painted with mercury-containing paint a median of 86 days earlier were compared with 16 homes not recently painted with mercury-containing paint. Paint samples from the exposed homes contained a median of 210 mg Hg/L (range 120-610 mg/L). The median air mercury concentration was higher in the exposed homes (0.3 microgram/m3; range nondetectable--1.5 microgram/m3) than in the unexposed homes (nondetectable; range nondetectable--0.3 microgram/m3, P less than 0.0001). Among the exposed homes there were seven in which paint containing less than 200 mg/L had been applied. In these homes, the median air mercury concentration was 0.2 microgram/m3 (range nondetectable--1 microgram/m3). Six (33%) exposed homes had air mercury concentrations greater than 0.5 microgram/m3, the acceptable indoor concentration recommended by the Agency for Toxic Substances and Disease Registry. Elemental mercury was the form of mercury released into the air. These data demonstrate that potentially hazardous mercury exposure may occur in homes recently painted with paint that contains mercury concentrations less than 200 mg/L.