"This subsidized [ethanol] program - paid for by taxpayer dollars - has contributed to pain at the cash register, at the dining room table, and a devastating food crisis throughout the world," McCain said in a statement.
A spokesman for the Environmental Protection Agency said regulators will consider the economic impact of renewable-fuel requirements when deciding whether to suspend the rules.
The agency has the power to waive or restructure federal requirements if they cause harm.
Spokesman Jonathan Shradar said the Bush administration remains committed to ethanol as an alternative fuel because of its potential to "get our nation off its addiction to foreign oil."
But lawmakers are questioning the consequences of using corn for fuel amid a global food crisis that has led to riots abroad and higher grocery bills at home.
Analysts say lawmakers are unlikely to roll back popular ethanol subsidies during an election year.
Congress will not "turn on the corn belt" because of the significant number of votes held by ethanol-producing states, analyst Kevin Book argued in a recent note to clients of his firm, Friedman, Billings, Ramsey & Co. Ethanol subsidies could face greater risks, however, in 2009 and going forward, according to Book.
Republican Senator Charles Grassley of Iowa said yesterday that "ethanol is unfairly taking the brunt of the criticism" for escalating food prices. Grassley's home state is expected to produce a quarter of all US ethanol this year.
Farmers have responded to federal ethanol incentives by planting the largest crop of corn in 60 years, leaving fewer acres for soybeans, oats, and other agricultural staples.
Tighter crop supplies means higher production costs for food processors of all types. In one recent example, Pilgrim's Pride Corp., the nation's largest chicken producer, said costs rose $200 million in the quarter on pricier corn and soybean feed.
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