Republican presidential candidate Herman Cain is on the air with his first campaign ad, a TV spot that argues federal regulations are hurting farmers.
The 60-second ad airing only in Iowa on the Fox News Channel mentions the oft-repeated but inaccurate claim that the federal Environmental Protection Agency supports regulating methane produced by livestock and dust.
The EPA under President Barack Obama has said it has no plans to regulate the gas, even though it is among greenhouse gases the agency believes are endangering human health. The EPA also said it will exclude dust created by agriculture from current air quality standards.
Iowa Republicans are holding their state's presidential nominating caucuses on Jan. 3.