Helium? Really? Explosive Helium
That must be some new kind of helium....
The key thing here is that the helium canister was inside the LH2 tank. It was apparently the initial even in the chain that led to the explosion of the vehicle. The canister could have exploded due to over pressurization, or a flaw in the material of its shell. The helium itself does not have to be explosive to cause such an event.
> Helium? Really? Explosive Helium
If I recall correctly the helium tanks contain helium gas under extremely high pressure. The gas is then released to maintain constant pressure during the burn. The weld securing the bracket holding the helium tank to the interior wall of the 2nd stage broke and the helium cylinder took off like a rocket and punched a hole in the 2nd stage, compromising it’s structural integrity. The ignition of it’s contents followed immediately thereafter.
Helium is used to pressurize the LO2 (liquid Oxygen) tank
Helium bottle broke lose and caused overpressure
Oh, the humanity!