What Sotera Health Company told the SEC could break it.

About 20% of Sotera's long-term Co-60 supply (the key gamma-sterilization input) comes from Russian reactors and could reach ~50% in a given year, exposing it to US/Canada/UK/EU sanctions and Russian countermeasures.

“We estimate approximately 20% of our long-term supply of Co-60 will be generated by Russian nuclear reactors. Further, over the next few years, we expect that there will be periods when, owing to planned or unplanned outages and variability in supply from reactors located in other countries, the proportion of our supply from Russian reactors may increase to as much as approximately 50% in a given year.”

In the U.S., Sterigenics' sterilization business relies on a single supplier for ethylene oxide (EO), a key input; a disruption could shut down portions of operations (mitigated by the supplier's redundant facilities and Sotera's self-supply license).

“For example, although there is more than one supplier of EO in most of the countries in which we operate, in the United States there is a single supplier for EO for our sterilization business.”

Within the Nordion (Co-60) segment, two customers were 34.8% and 11.0% of segment external net revenues in 2025 — significant single-customer concentration in that segment (Sterigenics and Nelson Labs have no >10% customers).

“For the year ended December 31, 2025, two customers reported within the Nordion segment individually represented 10% or more of the segment's total net revenues. These customers represented 34.8 % and 11.0 % of the total segment's external net revenues for the year ended December 31, 2025.”

About 45.9% of revenue and 47.6% of assets are outside the U.S.; a 10% USD appreciation would have cut 2025 revenue by ~$53.4M and gross profit by ~$29.2M.

“Approximately 45.9% of our revenues and 47.6% of our consolidated total assets as of December 31, 2025 were derived from operations outside the United States. Holding other variables constant (such as interest rates and debt levels), if the U.S. dollar had appreciated by 10% against the foreign currencies used by our operations in the year ended December 31, 2025, revenues would have been reduced by approximately $53.4 million and gross profit by approximately $29.2 million.”

Sotera faces expanding security controls and regulations on the transportation, storage, sale and import/export of radioactive Co-60, plus nuclear (CNSC) and FDA/health-regulator oversight of its hazardous EO/Co-60 operations.

“Because of increasing security controls and regulations regarding the shipment of materials including Co-60, we are likely to encounter additional regulations affecting the transportation, storage, sale and import/export of radioactive materials.”