A grand jury looking into a deadly Florida jail explosion says there isn't enough evidence to bring criminal charges.

Two inmates were killed and nearly 200 inmates were injured in the April 30 blast at the Escambia County Jail in Pensacola. It followed a torrential rain storm that flooded much of Florida's Panhandle.

In a report released by the State Attorney's Office on Thursday, grand jurors commended guards and the Escambia Sheriff's staff for their work during the explosion and flooding.

Jurors noted that a spark from an unknown source ignited natural gas and caused the explosion.

The grand jury made a number of recommendations for the county to consider as it builds a new jail.