Power plants won’t have to meet new limits until 2020 on toxic wastewater that comes from using air pollution control systems and transporting bottom furnace ash, the EPA announced Sept. 13.

The Environmental Protection Agency said it was postponing by two years compliance dates that would be required of more than 1,000 power plants nationwide, as it reconsiders how strictly it should limit those two sources of wastewater.

The postponement, requested by electric power utilities, applies to new Obama-era limits...