ASTM International panelists are in the process of developing a standard to assess vapor intrusion as it relates to property transactions. Vapor intrusion is caused by the release of volatile chemicals from contaminated soil and groundwater into indoor air spaces of overlying buildings, potentially causing both safety and health concerns. Panel meeting will be held in the future to determine if vapor intrusion is a recognized environmental condition (REC), which means site assessors would have to determine if chemical vapors that can contaminate indoor air through vents, porous concrete and other pathways may be present. Some environmentalists, mortgage lenders and others have suggested that if vapor intrusion is not considered a REC, it could lead to lawsuits against environmental consultants who did not consider it during site assessments or property owners who did not disclose the potential for indoor air contamination before a transaction.