Officials investigating the cause of the deadly explosion at a fertilizer plant in the town of West, Texas, say they have still not ruled out the possibility the fire was caused intentionally. Possible triggers under investigation include a problem with the plant’s electrical system, a battery-powered golf cart, or arson. A pair of blasts that happened almost simultaneously killed 14 people and leveled a residential area around the plant exactly one month ago today. Many of the dead were first responders who reacted to the initial fire.