So now they claim it was all about a mechanical failure? Something stinks about this.
That passenger must have laid a real gas bomb to cause the plane to gag!
This is probably a case of aerotoxic syndrome. Fresh air inside a moving airplane comes from air pressurized by the engines. This engine bleed air sometimes suffers contamination from leaking engine lubricants. When that happens, passengers and crew will experience toxic fumes consisting of vaporized lubricant and poisonous organophosphates used in it to deter insects and fungal and microbial growth. Airlines are reluctant to explain this in detail because of liability and customer relations concerns.