The cargo door of a 747 once cause a decompression that resulted in 9 passengers being ejected from 22,000 ft high!
In 1989, the forward cargo door of a 747 failed and opened up. The plane was carrying 3 crew members, 15 flight attendants, and 337 passengers. The incident caused 11 seats to be ejected and nine people died.
A flight attendant in the Business Class cabin was almost pulled out of the airplane, and was seen by passengers and fellow crew members clinging to a seat leg; they were able to pull her to safety inside the cabin, although she was severely injured. Another flight attendant in the Business Class Cabin hung on to the steps leading to the upper deck, and was dangling from them when the decompression occurred.
The pilots began an emergency descent to get the aircraft down into breathable air rapidly, while performing a 180-degree left turn to fly back to Honolulu. The decompression damaged components of the on-board emergency oxygen supply system, which was primarily located in the forward cargo sidewall area, just aft of the cargo door.