PLANTATION, Fla. – Who is responsible for the explosion that left 22 people injured and several businesses destroyed July 6 at a shopping plaza in Plantation? State investigators couldn’t figure it out with the evidence they have, and unless there is new evidence, the case will remain closed. According to a recent Florida Department of Financial Services report, an open natural gas valve at the vacant Pizzafire shop in the Market on University plaza, 1041 S. University Dr., caused the 11:28 a.m. explosion. Investigators reported they just don’t know who opened the valve at the north end of the plaza. Investigators wrote the “air conditioners were left on in the space because the agent was showing the space to prospective renters.