By Thomas Taylor Studies from the U.S. Environmental Protection Agency state that Americans spend 90 percent or more of their lives indoors1. This is one reason why the USGBC’s LEED 2009 rating system, which is being used by most project teams that have potential LEED-certified projects in the works, rewards teams from keeping harmful materials out of the facilities they build. Almost all manufactured materials used on construction sites contain some amount of chemicals. The truth is, chemicals that emit harmful gasses into the air, a process that is known as off-gassing, can be found in all sorts of other … Read more