In 2012, a submarine and a guided-missile cruiser collided off the coast of Florida during a training exercise.

The Navy has been investigating the accident ever since and has come up with a report in response to a Freedom of Information Act request filed by news outlets more than a year ago.

According to the Navy, the accident was a result of human error.

“The San Jacinto was one of two ships that was supposed to protect the USS Harry S. Truman as part of the exercise, while the Montpelier was playing the role of aggressor. the San Jacinto wasn’t fully focused on the anti-submarine warfare exercise because it was distracted with higher-priority carrier flight operations, among other things,” the report states.

The report also blamed the Navy’s chain of command and accused them of not planning out the exercise properly.

Human error led to 2012 collision between submarine, cruiser, .@USNavy says: http://t.co/xH7GX3wlNM pic.twitter.com/pa2TjSXezk

— Stars and Stripes (@starsandstripes) June 10, 2014

The Navy claims that the accident has been a learning experience and has allowed them to plan more carefully for current and future exercises.

“The number one priority of any exercise is safety. This must be ingrained in our naval force. Regrettably, it is not,” wrote Adm. Bill Gortney, commander of U.S. Fleet Forces Command, in endorsing the investigation’s findings. “We must ensure the lessons learned from this accident are implanted into our officers and sailors. We will not repeat this failure.”

Although the accident was shocking, nobody was injured in the collision. Both ships suffered severe damage and had to be repaired.

The Montpelier’s rudder was dislodged as a result of the collision, but its propulsion plant was unaffected. The San Jacinto’s sonar dome had extensive metal deformation, tears and flapping metal with exposed wiring.

The cost to repair the two ships is estimated to be around $43 million.

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