SAN JOSE (KCBS) – The St. James Park post office in downtown San Jose was reopened Tuesday after an evacuation prompted by a mystery powder in a package that sickened three employees.

Investigators have now determined that the powdery substance feared to be hazardous was in fact some kind of herbal remedy that an elderly San Jose man had ordered from Taiwan to give to one of his children, postal service spokesman Gus Ruiz said.

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Four square blocks around the historic building at 105 North First Street were closed to traffic as hazmat crews tried to determine what had sickened the workers.

“They’re going to all be transported to local hospitals,” said Capt. Mary Gutierrez with the San Jose Fire Department.

Tony Houston watched as the three were taken to a tent set up in the parking lot behind the building for treatment.

“They’ve had them take off parts of their clothing,” Houston said, which was then hosed down.

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Gutierrez said that was normal procedure to ensure the hazardous substance did not wind up being carried to the hospital in the ambulance.

She said another 63 postal employees were ordered to shelter in place inside Valley Transportation Authority buses while hazmat crews investigated any possible exposure.

The incident began when a man sorting mail picked up a package that was leaking a yellow-green powder out one seam and handed it to another worker helping him sort.

Gutierrez said the two quickly developed sore throats, headaches and coughing. It’s unclear how the third worker was exposed to the powder.

The post office reopened by 10:30 a.m.

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