I cannot think of any restrictions that would not apply to gas powered truck that would not apply to battery or diesel trucks. Assuming that there are no gas leaks from the cylinders / truck then I would look for some other reason for the alleged headaches. Steve

To echo bigiains experience, I'm aware of a logistics firm who received an improvement notice relating to LPG powered trucks a couple of years ago. Staff were employed to re-work product in a shed on a cold day. Doors were 90% closed (roller shutters) to allow some ventilation. Staff were overcome by the fumes and emergency services had to attend. The way the company expained it to us at a later date, the trucks are normally efficient but if the engine is not kept in tip top condition, the potential for carbon monoxide release increases vastly. They have since improved their maintenance and working procedures.