Idaho School loses weapons grade plutonium.

A small amount of radioactive, weapons-grade plutonium about the size of a U.S. quarter is missing from an Idaho university that was using it for research, leading federal officials on Friday to propose an $8,500 fine.

The U.S. Nuclear Regulatory Commission said Idaho State University can’t account for about a 30th of an ounce (1 gram) of the material that’s used in nuclear reactors and to make nuclear bombs.

The amount is too small to make a nuclear bomb, agency spokesman Victor Dricks said, but could be used to make a dirty bomb to spread radioactive contamination.

“The NRC has very rigorous controls for the use and storage of radioactive materials as evidenced by this enforcement action,” he said of the proposed fine for failing to keep track of the material.