Three U.S. utility companies, including Exelon and Pacific Gas and Electric, have canceled their membership in the U.S. Chamber of Commerce in response to the powerful pro-business lobbying organization’s stance on climate change.

This Washington Post article, which reports on Exelon’s defection, cites a Chamber spokesperson as saying that the lobbying group’s message has become “muddled.”

The Chamber has long been a commanding anti-regulation voice — it has expressed opposition to Sarbanes-Oxley, among other rules. These climate-related issues mark the first time in recent years that members have expressed such strong opposition to the Chamber.

Exelon’s chairman and CEO suggested that the Chamber’s stance on climate change could prove more detrimental to businesses because its opposition might help prevent Congress from enacting new environmental laws, which likely would result in the Environmental Protection Agency (EPA) creating rules that would be “more arbitrary, more expensive, and more uncertain for investors and the industry than a reasonable, market-based legislative solution.” ###