The Federal Aviation Administration was concerned with the safety of escape slides on passenger jets even before the fatal crash at San Francisco International Airport last summer, NBC Bay Area reports.

After Asiana flight 214 crash-landed on the runway on July 6, passengers went for the inflatable emergency slides to escape the wreckage. But several of the slides reportedly malfunctioned, leading to increased panic in an already terrifying situation.

Of the 307 passengers aboard the plane, two died in the crash. A third died later from injuries relating to the incident.

Over the years, the National Transportation Safety Board "has recommended multiple improvements to escape slides, and the Federal Aviation Administration has collected thousands of complaints about them," NBC Bay Area reported.

The station also reported that two months before the Asiana crash, regulators issued a safety alert for slides on the Boeing 777-200ER — the model of jet involved in the crash.

In an FAA document written months before the Asiana incident, the agency wrote it suspected "corrosion" on slide releases may have stopped the safety devices from opening properly. The malfunction may “interfere with escape slide and raft deployment, prohibit doors from opening in armed mode and cause consequent delay and injury during evacuation of passengers and crew from the cabin in the event of an emergency," the FAA wrote.

Two slides inflated inside the cabin in the immediate aftermath of the Asiana 214 crash. Flight attendants were reportedly pinned underneath them. Crew members were forced to deflate the slides using an ax.

Yahoo News spoke with NTSB spokesperson Keith Holloway, who said he couldn't discuss an ongoing investigation. But he did clarify that the NTSB is not an enforcer but rather an agency that investigates and makes recommendations to the FAA.

Yahoo News reached out to the FAA for comment but received no immediate response.

The Huffington Post has reported that the FAA has no jurisdiction "over plans registered outside the U.S. and it is up to South Korean air regulators to enforce safety on Asiana flights."