@sohkamyung Those gas containers look like they're all of a suitable design and in good condition to me, so I don't see much danger.

The only issue is see is that the tanks aren't chained (although there are retaining walls), meaning metal gas bottles may be thrown around during a big enough collision, but that's mostly a blunt trauma risk really.

Metal propane tanks have a very large safety factor, as propane only needs 1220 kilopascals (177 psi) of pressure to keep it liquid at 37.8 °C, so explosions don't happen unless you have a tank that has been leaking gas for ages, leaving a lingering gas cloud and a source of ignition.