The first hydrogen fuel cell vehicle ever produced, the General Motors Electrovan was a converted GMC Handivan built to demonstrate the feasibility of fuel cell technology. Mounted on the floor of the van, 32 thin-electrode fuel cell modules were connected by 550 feet of plastic piping. Separate tanks for liquid oxygen, liquid hydrogen and potassium hydroxide were mounted in the back. It was only ever operated on the GM proving grounds and was retired soon after its debut.