Investigators suspect that a gas explosion sparked the fatal blaze, FDNY sources said. The way it blew like that it seemed like a gas explosion,” said Johnson. Dramatic photos taken from the scene show a firefighter on a tower ladder plucking a panicked child from a fire escape. Though early reports indicated a lithium-ion battery may have been responsible, investigators now suspect a gas leak triggered the explosion, FDNY sources said. The blaze was declared under control at 3:30 p.m. but small fires reignited throughout the rest of the afternoon, FDNY officials said.