The U.S. Environmental Protection Agency (EPA) has extended to June 24, 2013, the deadline for comment on two separate vapor-intrusion guidance documents. The first document is the OSWER (Office of Solid Waste and Emergency Response) “Final Guidance for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Sources to Indoor Air,” and the second is “Guidance for Addressing Petroleum Vapor Intrusion at Leaking Underground Storage Tank Sites.” Additional information about the guidance documents appears in Issue 453 of this Update.