IDAHO FALLS, Idaho (AP) — The Nuclear Regulatory Commission is investigating a recent incident at a plant that manufactures radioactive products in Idaho Falls.

The Post Register reports that a technician at International Isotopes was exposed to a radiation dose above the amount of exposure radiation workers are allowed to have in one year on Aug. 20.

The worked did not have any immediate adverse health effects, but was sent to a local hospital for blood tests and has since returned to work. The worker was transferring a radioactive material out of a storage cask when it slipped to the ground, leaving its shielded container.

He then picked up the material and returned it to its container, briefly exposing himself. International Isotopes manufactures radioactive products used to treat cancer and for other research and industrial purposes.