U.S. EPA to unveil new biofuel rule Tuesday

WASHINGTON, May 4 (Reuters) - The U.S. Environmental Protection Agency will unveil a draft rule measuring the carbon dioxide emissions from biofuels such as ethanol and biodiesel on Tuesday.

EPA administrator Lisa Jackson, Energy Secretary Steven Chu and Agriculture Department Secretary Tom Vilsack will discuss the new rule on a conference call Tuesday at 10 a.m. EDT (1400 GMT).

Known as the updated Renewable Fuels Standard, or RFS-2, the rule could have an impact on the use of corn ethanol by gauging not only the direct biofuel emissions given off during production and from vehicle engines, but possibly also "indirect land use change" emissions.

Ethanol groups and some lawmakers oppose indirect land use emissions measurements, which include any climate warming pollution caused when production of crops like corn for biofuels displaces other crops, forcing farmers worldwide to burn down forests to grow them.

Critics say the science of indirect emissions has not been adequately developed. (Reporting by Ayesha Rascoe; Editing by Marguerita Choy)