Engineer warns of tombstones unless Boeing tackles deadly toxic fumes issue on planes

A senior engineer sent a mail in to the bosses of Boeing in 2007 warning them that they could be looking for "tombstone" unless they take steps to solve the potentially deadly issue of toxic fumes on board passenger planes.

The engineer said in the mail that the airlines giant was completely aware of the problem and that some of the events that had been witnessed, including blue clouds of chemical compounds hovering above passengers' heads, Daily Express reported.

According to the mail, the toxic air issue that constantly forces pilots to wear oxygen masks was one of the grim issues faced by the aviation industry, yet passengers were totally oblivious about it.

According to the official Civil Aviation Authority records, the entire crew of a British registered Airbus was recently taken to hospital for toxicology tests followed by a "fume event" on an anonymous flight to Geneva.