On April 24, 2019, the NRC issued a Severity Level III Notice of Violation to Holtec International for a violation of 10 CFR 72.146(a), "Design Control." The violation involved Holtec's inadequate modification of certain multi-purpose canisters used for the storage of spent fuel. Specifically, Holtec failed to establish adequate design control measures for installing alternative four-inch stainless steel stand-off pins that were essential to the function of the multi-purpose canister."