An EPA ruling will require the Portland Generating Station to drastically cut emissions.
Under the ruling released Monday, the coal plant must reduce sulfur dioxide emissions by 81 percent over the next three years.
Sulfur dioxide has been connected to respiratory illnesses and aggravates asthma.
The Northampton County plant has been one of the state's biggest sources of sulfur dioxide, which the wind carries over to New Jersey.
The New Jersey Department of Environmental Protection asked the EPA over a year ago to enforce the Clean Air Act due to the amount of pollution the Upper Bethel Township plant sends across the Delaware River to the Garden State.
The plant is owned by GenOn.