An explosion has injured two people Wednesday morning behind the Plumbers and Steamfitters Local 773 on Luzerne Road in Glens Falls. The men, ages 36 and 55, went into a storage unit to get tables out for a Thanksgiving gathering. There was a strong smell of gas inside at the time and the explosion followed. There were two 20 pound propane tanks in the unit, but an exact cause hasn’t been determined.