The crisis at the damaged Fukushima Dai-Ichi Nuclear Power Station in northern Japan has raised worries about radiation risks. We spoke Tuesday with Jonathan Links, an expert in radiation health sciences. He is a professor at the Johns Hopkins Bloomberg School of Public Health in Maryland.

Professor L inks says workers w ithin the nuclear plant are the only people at risk of extremely high doses of radiation.

JONATHAN LINKS: "Of course, we don't know what doses they've received, but the only persons at risk of acute radiation effects are the workers."

For other people, he says, there may be a long-term worry. People can get cancer from low doses of ionizing radiation, the kind released in a nuclear accident.

Professor Links says scientists can use computers to quickly model where radioactive material has blown and settled. Then they measure how large an area is contaminated. He says if the situation is serious enough, officials could take steps like telling people not to eat locally grown food or drink the water.