Co-60 tariffs would undermine U.S. health care, SSWG warns
In a letter to the Office of the U.S. Trade Representative, the Source Security Working Group (SSWG) is urging the U.S. government to withhold from imposing tariffs on Canadian-orgin cobalt-60 and to preserve the duty-free treatment of the radioisotope.
Co-60 is used to sterilize about 40 percent of all single-use medical devices and is used to treat inoperable brain cancer. The import of Co-60 from Canada is duty-free under the 2020 United States-Mexico-Canada Agreement (USMCA); the radioisotope is also exempt from tariffs under the International Emergency Economic Powers Act (IEEPA).
SSWG is an alliance of professional organizations, including the American Nuclear Society, that seeks to ensure continued, safe, and reliable domestic access to radiological sources.
The letter: The SSWG submitted its letter in response to a request for comments by the Office of U.S. Trade Representative on an impending joint review of the USMC by representatives of the U.S., Canada, and Mexico. That review is scheduled for July 1, 2026. Notice of the request for comments was published in the September 17 Federal Register.
The SSWG letter states: “Retention of USMCA preferential treatment is essential to ensuring the continued, low-cost importation of Co-60 into the United States, thereby supporting medical device safety and patient health. Maintaining this preferential status—both under the USMCA and as an exemption from IEEPA-imposed tariffs on Canadian-origin imports—facilitates sustained U.S.-Canada collaboration in investment, innovation, and intellectual property development.”
Signatories of the letter include ANS, the American Association of Physicists in Medicine, the American Society for Radiation Oncology, Elekta Inc., the Gamma Industry Processing Alliance, and the International Source Suppliers and Producers Association.
Supply chain: According to Bruce Power, more than half of the global supply of Co-60 is produced in Canada from the Bruce Power and Pickering reactors. When including additional supply from global sources, Canada refines more than 90 percent of the Co-60 market globally.
In addition, Ontario Power Generation announced in February that Unit 1 of its Darlington nuclear power plant was modified to allow it to produce Co-60. OPG expects to harvest the isotope during Darlington-1’s next planned maintenance outage, sometime in late 2026–early 2027.
The SSWG notes that the current domestic supply of Co-60 does not meet the medical demand in the United States. Westinghouse is currently working with Nordion to produce Co-60 in U.S. pressurized water reactors. The insertion of cobalt targets, however, is not expected until late 2026, with Co-60 production by 2029–2030, according to the SSWG.
“Any disruption to the USMCA’s duty protections or imposition of new tariffs—on Co-60 or uranium imports from Canada—would threaten this effort and undermine U.S. health care capacity,” the SSWG letter states.
