The US NTSB is investigating a 26 October incident involving an American Airlines Boeing 757 that experienced rapid depressurisation at 31,000ft en route from Miami to Boston.
According to the FAA, the oxygen masks were deployed after the depressurisation, later determined to be caused by a 0.3m x 0.6m (1ft x 2ft) hole that opened up just behind and above the left side front cabin door. The picture below was posted the Professional Pilots Rumour Network (Pprune.org).
The crew of flight 1640 declared an emergency and descended, landing safely back in Miami with no injuries to the 154 passengers and six crew on board.
NTSB says it sent two investigators to inspect the damage to the aircraft, and will possibly bring a section of the damaged area back to Washington for examination. The inspectors also retrieved information from the flight data and cockpit voice recorders.
Flight's ACAS database shows that the aircraft, N626AA, had accumulated 62,278h and 22,093 cycles as of 31 July. The aircraft had no reported damage history, and most recently had winglets installed at 57,989h.