Volatile Organic Compounds
V.O.C.s are present in stain products in the form of solvents. As the stain dries, the compounds evaporate and dissipate in to the air.
The maximum level of V.O.C.s allowed is 550 grams per liter (550 VOC), but some states are more strict and only allow 250 g/l (250 VOC). Certain counties in California only allow the use of zero V.O.C. (0 VOC) products.