Fresh 737 Max safety fears as debris is found in fuel tanks after planes grounded over 356 deaths

SEVERAL of Boeing's crisis-hit 737 Max passenger jetliners pose a gigantic safety risk after debris was found in the fuel tanks of planes in storage — waiting to be delivered to airlines.

Since the planes were banned from the air over air disasters that left 346 dead, the head of Boeing's 737 programme had told employees that the damning discovery was "absolutely unacceptable".

But a Boeing spokesman said the company did "not see the issue" in further delaying the jet's return to service.

It comes as the 737 Max remains grounded after two fatal crashes.

According to an internal memo, foreign objects, an industrial term for rags, tools, metal shavings and other materials left behind by workers during the production process, has been a quality control issue for various Boeing aircraft, such as its KC-46 tankers.

Mark Jenks, general manager of the 737 program, told employees that the company was "taking steps to address the issue" in its production system.

The objects were found during maintenance work on some of the hundreds of 737 MAX jetliners Boeing has built but not delivered due to a worldwide ban imposed last March following two crashes, he said.

The Federal Aviation Administration (FAA) did not immediately respond to a request for comment.

The 737 Max was grounded in March 2019 after air disasters in Indonesia and Ethiopia left 346 dead.

Worried Boeing workers thought the controversial 737 Max passenger jet was "designed by clowns" — damning internal communications reveal.

The highly-revealing messages show employees slamming the plane, their bosses and the FAA.

In one exchange — before the first of the two deadly crashes — an unnamed employee asked: "Would you put your family on a Max simulator trained aircraft? I wouldn't."

Another fumed: "This airplane is designed by clowns who in turn are supervised by monkeys."