American Electric Power's plan to shutter a string of aging coal-fired electric plants if regulators adopt strict new pollution rules is likely the first in a string of similar decisions that has the coal industry bracing for waning demand.

The AEP warning came in response to new rules proposed for coal-fired power plants by the U.S. Environmental Protection Agency.

National Mining Association spokeswoman Carol Raulston says the coal industry expects more utilities to issue similar warnings.

Raulston says her organization has produced one of numerous studies about what would happen if the EPA rules take effect. But she says no one really knows, though it's widely expected that natural gas producers would benefit at the expense of coal companies.

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