Burps from cows and other farm animals won't be regulated under proposed greenhouse gas legislation being looked at by the U.S. Congress.



Although the Environmental Protection Agency wasn't planning to regulate cow burps in the first place, worries over the far-off possibility of a "cow tax" prompted the exclusion of a specific gas from the legislation.



The largest source of methane in the U.S. is cow, pig and sheep burps. They produce 25 percent of the methane put out by the U.S. and account for 2 percent of all the U.S. emissions that contribute to climate change.



Enteric fermentation, the process in some animals that produces methane, is excluded from any possible greenhouse gas limits, and the legislation also aims to exclude it from any new standards, such as those being proposed for smokestacks and vehicle tailpipes.





The origins of the cow tax can be traced to last July, when President George W. Bush's EPA released documents outlining how the Clean Air Act could regulate greenhouse gases.



Even though the Bush administration had no intention of using the law, farm groups seized on a single paragraph deep in the comments from various federal agencies. The Agriculture Department warned that if EPA decided to regulate agricultural sources of greenhouse gases, numerous farms would face costly and time-consuming process to acquire permits for barnyard burping.



From there, farms groups cautioned that if farms had to purchase air-pollution permits like factories and power plants - which have more options for limiting and controlling emissions - it would be like taxing farmers for having livestock.While that leaves a source of greenhouse has emissions unchecked, it's also clear that methane from cow burps can't be approached the same way as factory emissions. Buildings can be retrofitted or built with pollution-limiting technology. Animals can't.

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