Granules of crushed chickpeas mixed with sesame oil and spices make a yummy Mediterranean treat called hummus.

Granules of crushed chickpeas left in an unidentified small plastic bag at the post office make for a hazardous materials threat.

Postal officials could not determine who left the bag or what was in it, said Casper Fire-EMS spokesman Jason Parks.

So at 10:15 a.m. Tuesday, they called the Casper Fire-EMS Department, which responded to the loading dock area of Casper's main post office at 411 N. Forest Drive, Parks said.

The department sent three fire engine companies with a hazardous materials response vehicle, a ladder and rescue truck, a command vehicle, and a response vehicle from the City of Casper-Natrona County Health Department, he said.

Because it was in a locker room, it did not affect the mail service, Parks said.

Even though the substance probably wasn't harmful, the responding crew needed to take appropriate precautions before entering the area, Parks said. Firefighters suited up in their hazmat suits.

The two who entered took a large briefcase-size kit capable of determining the nature of the substance.

If the substance had tested positive as a biological agent, the health department would have taken over the investigation and sent it to the state laboratory's bioterrorism lab in Cheyenne, said department spokesman Marty Thone.

The substance-identification kit, Parks said, determined with 95 percent to 98 percent certainty that the substance was hummus.

Parks added he had never tried it.

Reporter Tom Morton can be reached at (307) 266-0592, or at Tom.Morton@casperstartribune.net.