Gov. Tom Corbett is expected in Pittsburgh at a rally of coal industry supporters who oppose stricter Environmental Protection Agency regulations for coal-fired power plants.
Wednesday's rally at a minor-league soccer stadium comes a day before the EPA holds two days of public comment hearings in the city starting Thursday. Hundreds of people are expected to testify in Pittsburgh, as well as at hearings in Atlanta, Denver and Washington on Tuesday and Wednesday.
Business and labor officials say the regulations will drive up electricity prices and cost jobs in the coal and energy industries. That resonates in Pennsylvania, the nation's fourth-largest coal-producing state.
Environmentalists say the rules will combat climate change and benefit the economy in the long run by producing jobs relating to more renewable, efficient energy sources.