An apparent explosion and fire at a propane supply company on Vashon Island sent three people to area hospitals Friday afternoon, one with third degree burns. 911 dispatchers got a call around 12:30 p.m. of an explosion at Vashon Energy at 20317 Vashon Highway Southwest. Witnesses said passers-by went into the one story building that was already on fire to help employees escape. When fire crews arrived, the building and two cars were already engulfed in flames but their main concern were propane storage tanks both inside and outside the building.