Dozens quarantined, 3 sick, after US Customs receives suspicious envelope at California office

Up to 50 people were quarantined Wednesday after an employee opened envelope with a suspicious powdery substance in an United States Customs office in Alameda, California. In the end, no substance was found, but an investigation is underway.

A 2:43 pm emergency call was made reporting the employee feeling sick immediately after opening the envelope, KNTV reported.

Two more people also felt sick. Fire officials found their symptoms were not deadly, but the workers received treatment under quarantine, and a HAZMAT crew was on location telling others to stay away from the area.

Fire officials established a "hot zone," an area where safety equipment is required to avoid the risk of infection.

The responding hazardous materials team was unable to find the substance, but the envelope, which was addressed to the federal office and sent by a private carrier, was taken to a lab, officials said.

 “Once we identify what it is,” Alameda Fire Department Spokesman Juan Medrano told the San Francisco Chronicle. “we can figure out how to deal with the substance itself and what levels of decontamination are needed.”

Before the quarantine was officially called off shortly before 4:00 pm, police Lt. Jill Ottaviano told El Cerrito Patch that some people were allowed to leave the building.