IMAGINE THAT the Boston bombers didn’t pack nails into pressure cookers but instead packed highly radioactive material. How would the government be responding?

Part of the answer might lie in a document the Environmental Protection Agency (EPA) issued this month, suggesting guidelines on how state and local officials should deal with potentially toxic nuclear contamination from disasters such as dirty bombs, power plant failures and atomic bomb detonations.

Activists object that the guidelines would expose Americans to high doses of radiation instead of ensuring high levels of protection. The unsubtle subtext is that the continuing use of nuclear power is a direct danger against which the government is failing to protect people.

Actually, nuclear power has an exceptional safety record, particularly compared with the illnesses and deaths for which air pollution from coal burning is responsible. It also poses unique risks for which the government should prepare responsibly. That’s just what the EPA is doing.

The critics say that the EPA is attempting to defy long-established legal standards for radioactive contamination. The document, they say, would allow Americans to drink water contaminated thousands of times past the legal limit. It would allow residents to remain in a disaster zone even when there’s lots of dangerous material in the air. And, they claim, the EPA’s suggestions would allow resettlement of areas that are unfit under the rules that govern toxic Superfund sites.

The EPA responds that the government’s legal safety standards haven’t changed. The new guidelines aren’t enforceable rules — they are suggestions to help local officials make tough decisions. In fact, the guidance repeatedly refers to meeting existing standards, not flouting them. The question, though, is how to handle a big radiological release in the real world.

Following a nuclear disaster, it could be a long time before radiation meets the EPA’s usual safety levels. In the meantime, when is it absolutely necessary to restrict the water people can drink or to abandon an area? Moving people out of a hospital’s intensive care unit, for example, poses its own risks. And when is it safe enough to move back (with precautions)? There are costs to keeping people out of their homes and away from their jobs for long stretches. Repaving roads and restricting crop growth, for example, might make an area habitable while cleanup continues. The guidance encourages local officials to think about these questions — with some sense of where the threshold contamination levels might lie — before they have to make those calls.

The activists are right, though, about one thing: The document is a confusing bore. If the EPA wants city, county and state officials to pay attention — if it wants to make the case for practicality over the activists’ hyperbole — the agency ought to rewrite the guidelines in plain English.