A Delta Airlines Boeing 757-200, registration N686DA performing flight DL-339 from Atlanta,GA to Seattle,WA (USA) with 185 passengers and 7 crew, was enroute at FL280 about 310nm eastsoutheast of Denver,CO (USA) when the crew initiated an emergency descent (average sink rate 4500 fpm), the passenger oxygen masks deployed. The aircraft subsequently diverted to Denver for a safe landing on runway 35L about one hour after leaving FL280. Six passenger requested medical assistance, two of them were taken to a hospital, 4 of them were checked at the airport.
The airline reported a depressurization event, the passenger oxygen masks deployed. The crew descended the aircraft to 10,000 feet and diverted to Denver.
A replacement Boeing 737-900 registration N876DN reached Seattle with a delay of 4:45 hours.
The aircraft was subsequently seen with the engine access doors open on both engines.
The occurrence aircraft is still on the ground in Denver about 40 hours after landing.