California pursues low-carbon fuel constraints

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* Low-carbon fuel standard would be first in nation

* Measure aims to spur alternative fuels market

* Ethanol industry says proposal is flawed, unfair

By Steve Gorman

LOS ANGELES, April 22 (Reuters) - California on Thursday is expected to adopt landmark rules to curb carbon emissions from transportation fuels despite intense opposition from some who say the proposal is biased against corn-based ethanol.

If adopted by the state's influential air quality regulators, the low-carbon fuel standard would become the first measure in the nation to impose on motor fuels limits on the amount of greenhouse gases that contribute to global warming.

Similar rules are under consideration in 11 other states that are waiting for California to act. President Barack Obama also has called for a nationwide low-carbon fuel standard to help meet his goal of cutting greenhouse gas emissions more than 80 percent by mid-century.

California's proposal takes a sweeping "cradle-to-grave" approach that aims to reduce the carbon footprint of fuels from production to combustion. It also seeks to spur development of cleaner-burning alternatives to gasoline and diesel fuels that will help abate climate change and reduce oil imports.