Yes they are safe! I The standards governing the construction of the various LPG components are very strict. Products that are installed in cars have been designed and manufactured taking into account the chemical and physical characteristics of LPG. LPG tanks are made from 3.5 mm steel plate that has been heat-treated to prevent cracking in the event of deformation (caused by an accident, for example).
During the homologation process, the LPG tanks are subjected to a hydraulic pressure test and must not show any structural failure up to a pressure of 67.5 bar.
Suffice it to say that the pressure developed by the LPG inside the tank normally ranges from 3 to 7 bars. In contrast, the petrol tank is made of plastic and melts at 160°-170°C and softens at 120°C.
Finally, LPG pipes are made of metal, while petrol pipes are made of plastic or rubber.