Republican Illinois U.S. Sen. Mark Kirk said a U.S. aircraft carrier was slightly contaminated with radioactive material Sunday.

The USS Ronald Reagan has been stationed off the coast of Japan. Several nuclear facilities were damaged after last week’s earthquake and tsunami.

Kirk said countries should re-examine where their nuclear reactors are located.

“It was the tsunami that wiped out the cooling system,” Kirk said. “And so we have to look at the location of these reactors and understand at any future sighting decision, we have to take that into account.”

Kirk says it’s difficult for the U.S. military to provide support for Northern Japan because of the explosions at nuclear plants.