The USS The Sullivans suffered minor damage during testing of a Standard Missile 2, one of the Navy's go-to surface-to-air missile. None of the ship's 278 crewmen were injured in the incident, the Navy said in a statement.
The Arleigh Burke-class destroyer was sailing off the coast of Virginia as part of planned missile exercise. Damage was limited to the port side of the ship, near the helipad on the stern, where a small fire broke out, Foxtrot Alpha reports. The Sullivans sailed back to Naval Station Norfolk for a full damage assessment under her own power.
At this point, it's not clear what caused the SM-2 to malfunction, although USNI News reports that it was an older Block IIA missile. As Foxtrot Alpha says, the explosion could simply be the result of age and years of being battered at sea. Thankfully, the missile's 137-pound high-explosive, fragmenting warhead was not armed during the launch.
According to the Navy's statement, the Naval Sea Systems Command's Program Executive Office for Integrated Warfare Systems is investigating The Sullivans incident. You can read the full release from the Navy below.