Hyundai is recalling 239,000 cars because the seat belt pretensioners can explode and injure vehicle occupants... a not-so-great occurrence that has happened to five people.

I thought a pretensioner was the part of the seatbelt that tightens when you accidently pull the strap down too fast when you're running late… or when you get in a crash. But it's even crazier than that:

During a collision, the pretensioner utilizes an explosive charge to initiate a concealed piston once the sensors detect that an accident has occurred. The piston proceeds to drive the spool rapidly around, which the fabric strap of a seatbelt is wrapped, thereby removing any slack from the seat belt.

This guy shows us how to activate one with jumper cables (just don't use a Hyundai version):

Basically, it's the part that saves your life.

But not anymore! Now, it's a grenade just waiting to go off.

At least, that's the case if you own Hyundai's 2019-2022 Accents, 2021-2023 Elantras and 2021-2022 Elantra HEVs, or hybrid electric vehicles.

In a letter to the Korean automaker, government regulators said,

The driver's and front passenger's seat belt pretensioners can explode upon deployment and send shrapnel throughout the vehicle.

If you do own one of the affected vehicles, a Hyundai dealer will add a cap at no cost to prevent the shrapnel issue, and as an additional service, they'll also upsell you on ten other things they could go ahead and work on while you're there.

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