A cloud of ammonium sulfate billowed into the face of a postal worker after he opened a curbside mailbox Monday, prompting concerns it may have been planted to harm the man.
The postal worker, whose name was not released, was emptying a mailbox at 850 E. 300 South about 10:30 a.m. when he set a box down on top of a stack of other mail, said Salt Lake Fire Capt. Devin Villa. As the pile of mail compressed under the weight of the box, a powdery substance floated up into his face from the bottom of the stack.The worker was treated by paramedics at the scene and released in good condition.
The substance was later identified as ammonium sulfate, a compound used as a fertilizer and in some fire extinguishers, Villa said.
Investigators from the post office said Tuesday they had determined that the substance had come from a fire extinguisher. It did not damage or delay any mail, a spokeswoman said.
Investigators are looking into whether the ammonium sulfate was put there to harm postal workers, Villa said. The FBI looked into the matter Monday, but is leaving the investigation up the postal service, special agent George Dougherty said.
The wind apparently blew the substance into the man's eyes and mouth, causing his eyes to burn and his mouth to dry out, a post office spokeswoman said. The carrier was feeling fine on Tuesday.