The article discusses the emerging issue of vapor intrusion in environmental law and real estate transactions. It explains that vapor intrusion is when subsurface contaminants emit vapors that travel through the soil or in groundwater, which release volatile organic compounds. Theoretically, the vapor can intrude into buildings and has been a source of property damage and health hazard claims. The article discusses remedial efforts, reviews recent lawsuits and provides advice as to how corporations can mitigate vapor intrusion risks. Also addresses insurance coverage for vapor intrusion, particularly focusing on environmental claims and CGL policies.