it is not an airplane problem (how do they know), but a medical problem affecting 10 passengers
The report mentions "eye irritation and difficulty breathing", which sounds very much like oil or hydraulic mist/fumes.
A/c reportedly operates in a 50-seat configuration for the DoJ/US Marshals Service and was carrying 12 passengers and 5 crew. Hmmm. No mention of whether they included Nicholas Cage or John Malkovich.
