According to the Mohawk press release:
Mohawk specifically cited the Chamber's efforts to derail Congressional climate and energy bills, and its call on EPA for a "Scopes Monkey Trial"  debate on man-made climate change, as reasons for exiting the Chamber.
The Yes Men punked the Chambe r yesterday in a fake news conference, drawing Chamber spokesman Eric Wohlschlegel into an uncomfortable position when real reporters started asking him why the Chamber is clinging to its position denying climate change. After stumbling through a few defensive replies, Wohlschlegel handed out business cards and left the scene.
The Huffington Post reported  last week that MacAndrews & Forbes Holdings, the holding company owned by multi-billionaire Ronald Perelman, is also debating whether to leave the U.S. Chamber of Commerce over its extreme climate position and “Scopes Monkey Trial” challenge to the EPA over the Clean Air Act.
The Chamber has been losing members – real members out of its actual 300,000 or less total  – at a rate of several each week lately. Apple was the most recent  in a string of high-profile defections including Exelon , Pacific Gas & Electric, PNM Resources , Nike , Levi Strauss & Co., PSEG , and the San Francisco Chamber of Commerce .
Mother Jones magazine has done several  excellent  pieces  recently explaining the reasons behind the exodus , including an excellent article titled “Inside the Chamber of Carbon.” 
Who will be the next to abandon the rapidly-shrinking Chamber  over its extreme climate position?