SEATTLE (Reuters) - A Washington state lawmaker has apologized for telling a bike store owner, in a spat over a proposed bike fee, that bicyclists can cause pollution - just by breathing out carbon dioxide.

Ed Orcutt, a ranking Republican member of the state House of Representatives Transportation committee, said in an email exchange with a bike shop owner that drivers and bicyclists should both share the burden of preserving the roads they use.

"You claim that it is environmentally friendly to ride a bike," Orcutt wrote to Dale Carlson, the owner of three bicycle shops in the Tacoma and Olympia areas who voiced concern that a proposed $25 fee on bicycle sales of $500 or more could hurt his business.

"But if I am not mistaken, a cyclists has an increased heart rate and respiration ... Since CO2 is deemed a greenhouse gas and a pollutant, bicyclist are actually polluting when they ride," Orcutt wrote late last month.

On Monday, Orcutt hit the brakes and made a U-turn.

"My point was that by not driving a car, a cyclist was not necessarily having a zero-carbon footprint," Orcutt wrote in an email delivered to constituents. "In looking back, it was not a point worthy of even mentioning so, again, I apologize."

Orcutt, who has been a member of the Washington state House since 2002, said he supports the fee for bicycles to help pay for street infrastructure, but little else from a revenue package proposed by House Democrats two weeks ago that would raise roughly $9.8 billion over 10 years by raising taxes, among other proposals.

"The idea of bicyclists paying for some of the infrastructure they are using is one which merits consideration," Orcutt wrote.

Carlson, the owner of the stores, wrote an email to lawmakers on the House Transportation Committee, saying cyclists should not be discouraged from an activity that is healthier for humans and the planet.

"I thought it was so off the wall - that (Orcutt) was being sarcastic or something," Carlson told Reuters.

Orcutt is correct that a human likely produces more carbon dioxide while riding a bicycle than sitting in a car, but that is part of the natural cycle of human metabolism, said Thomas Ackerman, a professor of atmospheric sciences at the University of Washington.

"It's a question of where that CO2 comes from," Ackerman said. "CO2 is only a pollutant when it comes from fossil fuels."