Commercial Irradiators

Irradiators are machines that expose products to gamma radiation to kill germs and insects or for 

other purposes. Food, food containers, spices, fruits, plants and medical supplies are the products most 

commonly irradiated. The process does not leave radioactive residue or cause the products to become 

radioactive. The radiation can come from radioactive sealed sources, an x-ray tube or an electron beam.

The NRC and its Agreement States regulate the use of irradiators that use sealed sources. These 

states have agreements with the NRC permitting them to regulate most of the radioactive materials used 

within their borders. The states regulate x-ray generators and electron beam irradiators. 

Irradiators have been used in this country for more than 50 years. The NRC does not specify 

what products may be irradiated, nor does it have a position on food irradiation. The U.S. Food and 

Drug Administration and other agencies have approved the irradiation of meat, poultry, and fresh fruits 

and vegetables. 

Sealed sources must be carefully controlled and handled at all times to avoid worker 

overexposure to radiation. All commercial irradiators regulated by the NRC use cobalt-60 as their 

source. There are two types of U.S. commercial irradiators using radioactive sealed sources: underwater 

and wet-source-storage panoramic models.

Wet-source-storage panoramic 

irradiators store their sources in water. 

When products move into the room on 

a conveyor, the sources are raised into 

the air. Once the product has been 

irradiated, the source is lowered back 

into the pool. Thick concrete or steel 

walls and roofs protect workers and 

the public when the sources are lifted 

from the pool.

Underwater irradiators use 

sources that remain in the water at all 

times, providing shielding for workers 

and the public. The product to be 

irradiated is placed in a water-tight 

container, lowered into the pool, 

irradiated and then removed.

h
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Properly designed and operated commercial irradiators operate safely and securely and pose no 

significant risk to workers or the public. In most cases, exposure to workers is so low it cannot be 

detected or distinguished from natural background radiation. (Each year, Americans receive about 300 

millirems due to background radiation from natural sources.) The significant shielding required for these 

facilities means the public receives little, if any, exposure from the sources. NRC regulations limit the 

exposure to the public from a licensed facility to 100 millirems per year. 

There are about 50 commercial irradiators in the United States. State and local governments can 

use zoning and planning laws to determine where an irradiation facility may be built.

Licensing and Inspection

Irradiators that use radioactive material must meet all safety and security requirements. These 

include:

• A company must have a license from the NRC or an Agreement State before obtaining a 

radioactive sealed source.

• Irradiator facilities and sealed sources must meet design and performance criteria.

• Irradiator facilities must undergo construction monitoring and acceptance testing.

• Operators must meet regulations for operating and emergency procedures, inspection and 

maintenance, and worker training.

• Operators must be able to detect, assess and respond to any actual or attempted unauthorized 

access, and must also report any unauthorized access or other suspicious activities to the NRC.

NRC and Agreement State license reviewers focus on radiation safety, facility security, the 

source’s integrity, safety system design, and personnel training and experience. The NRC periodically

inspects irradiators to ensure compliance with the regulations. If a facility fails to comply, NRC 

enforcement actions can range from ordering changes to assessing fines or even revoking a license.

Accidents and Contamination Events

The only serious radiation exposure events at U.S. irradiators involved two radiation-related 

injuries decades ago. In June 1974, an operator in Parsippany, N.J., walked into a room with an exposed 

source, saw it and quickly left. He developed observable symptoms of radiation sickness. In September 

1977, an operator in Rockaway, N.J., entered a room while a source was unshielded. This worker also 

received a dose large enough to cause radiation sickness symptoms. Both overexposures occurred 

because of bypassed safety systems or failure to follow procedures. Two other workers died, unrelated 

to radiation exposure, in an accident moving materials to be processed at a U.S. irradiator. 

Two cases of contaminated soil at U.S. irradiators required extensive cleanup. In 1988 in 

Decatur, Ga., an irradiator source leaked. The source dissolved easily in water, similar to table salt. The 

leak contaminated the facility and some surrounding soil. The cleanup work was costly to the facility’s 

operator and the U.S. Department of Energy, which had supplied the source. No members of the public 

were exposed. In Dover, N.J., in 1982, a damaged cobalt-60 source contaminated water that was 
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released to the facility floor and surrounding soil. Extensive cleanup was required, but again there was 

no exposure to the public. Neither event affected groundwater sources.

The NRC reviewed the causes of various incidents, developing strict requirements designed to 

reduce the risk of future incidents. They ensure the facilities have safety features and redundancies to 

minimize the possibility of radiation exposure to workers and the public, and security measures to 

prevent unauthorized access to the sources. These regulations, implemented in 1993, are known as 10 

CFR (Code of Federal Regulations) Part 36 and 10 CFR Part 37, respectively.

The 2011 earthquake and tsunami that struck the Fukushima Daiichi nuclear power plants in 

Japan prompted the NRC to review the generic facility design of commercial irradiators to determine if 

engineering controls and barriers are sufficient to protect the health and safety of the public and workers 

in the event of similar natural disasters. The NRC concluded that natural phenomena such as tsunamis, 

earthquakes, hurricanes, or fire are unlikely to cause a loss of control of radioactive material that might 

harm the public or the environment.

Shipment and Disposal of Radioactive Sources

Suppliers of radioactive sources must ensure their shipping packages are sufficiently robust and 

meet NRC standards. They must also follow U.S. Department of Transportation regulations when they 

transport radioactive materials. The sources are usually returned to the supplier once their radioactivity 

levels have dropped and they can no longer efficiently irradiate material. Again, NRC and Department 

of Transportation requirements must be met when sources are returned.

Security of Radioactive Sources

The NRC’s security requirements for irradiators account for possible hostile actions. While no 

specific credible threats have developed against U.S. irradiators, the NRC required enhanced security at 

irradiation facilities after the events of September 2001.

Before receiving a license, the facility owner must take very specific actions to secure the 

irradiator and its sources. Those measures must be in place before radioactive sources are loaded into the 

irradiator. The NRC has considered a number of scenarios involving a terrorist obtaining a radioactive 

source and using it to build a so-called “dirty bomb.” That review found it would be extremely difficult 

to use a cobalt-60 source to contaminate a wide area.

Emergency Procedures

The NRC requires irradiator operators to coordinate with local and state emergency response 

agencies in case of an emergency. Operators must have procedures for handling a variety of 

emergencies, including fires, earthquakes, tornadoes, loss of power, leaking sources and water leaks

from the storage pool. Those procedures must be in place before the NRC will issue a license.
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Decommissioning

As with all licensed nuclear facilities, irradiation facility sites must be decommissioned once 

they permanently close. This work includes safely disposing of radioactive sources and removing any 

contamination above acceptable levels. Before this work can be considered complete, the facility 

operator must do surveys to ensure the site meets applicable safety and health standards. The operator 

must also provide the NRC with assurance that it will have sufficient money to decommission the 

facility in a timely way.

February 2020