The U.S. Nuclear Regulatory Commission has denied a petition from numerous environmental groups asking to expand safety and evacuation zones around nuclear power plants.
Federal officials said the current 10-mile radius is sufficient in the event of a nuclear disaster at plants, such as Peach Bottom Atomic Power Station and Three Mile Island.
"There's already a framework there to protect the public," said Neil Sheehan, NRC spokesman.
But a lot of lawmakers and residents disagree with that decision.
Three Mile Island Alert and 37 other groups, including Greenpeace and SEED Coalition, petitioned for the change.
Members of Three Mile Island Alert did not return correspondence seeking comment about the decision.
The petitioners could take up the issue in federal court, Sheehan said.
U.S. Sen. Bob Casey, D-Pa., said he would also push for change.
"It is imperative that we ensure the safety of all Pennsylvanians in the event of an incident. I'll continue to press the (Obama) administration and the NRC to lay out plans to protect residents who could be potentially impacted by a nuclear event," he said.
Casey was one of a handful of senators who asked the Government Accountability Office, which is the investigative arm of Congress, to review evacuation zones after an Associated Press report in 2011 exposed weaknesses in community planning for nuclear accidents.
"More than 10 million Pennsylvanians, which is 80 percent of our population, live within 50 miles of a nuclear power plant. We need to ensure that appropriate plans are in place and that residents are fully informed about emergency procedures outside of the 10-mile radius," he said.
The GAO investigation determined, in the event of a nuclear plant accident, panicking residents from outside the 10-mile evacuation zone might crowd roads and prevent others from leaving.
For more than 30 years, emergency plans at nuclear power plants have focused on the 10-mile radius and are updated on an as-needed basis, Sheehan said.
"Emergency plans are living documents and constantly need updated," he said.
For example, plants review new Census data every 10 years and update their response time accordingly.
Exelon Generation, which owns both Peach Bottom and TMI, deferred questions to the Nuclear Energy Institute, saying the lobbying group in Washington, D.C., was best suited to answer questions about the industry.
A spokesman for the institute did not return a call seeking comment.
—Reach Candy Woodall at email@example.com.