The Environmental Protection Agency is expressing confidence that the Supreme Court won't block its limits on mercury and other hazardous air pollutants.

The high court has agreed to review a case claiming the EPA failed to consider costs when deciding whether to regulate certain pollutants from coal- and oil-fired power plants. A federal appeals court upheld the rules in April.

EPA Administrator Gina McCarthy says the agency is "very confident" it will win the case. She says the Supreme Court is only examining a narrow issue.

McCarthy says the government is on solid ground in regulating mercury. She says the agency is already working on implementation and ensuring compliance for the mercury rule. She says the EPA doesn't expect the Supreme Court's review to delay the process.