A suspicious letter containing a white powdery substance prompted evacuations at the Council on American-Islamic Relations Bay Area office in Santa Clara on Thursday.
CAIR's regional executive director Zahra Billoo said the office received a letter around 12:30 p.m. which contained a suspicious substance. The sender put his name down as "Infidel."
The office is located at 3000 Scott Blvd. The building was evacuated and about 12 employees who were inside were quarantined by Santa Clara police and fire department officials. NBC Bay Area chopper video showed people in yellow hazmat suits being hosed off.
Three people were taken to the hospital as a precaution, authorities said.
CAIR workers notified police and the FBI soon after the discovery, according to Billoo. Firefighters said Hazmat crews were taking samples that will be tested in a laboratory.
Santa Clara Battalion Chief David Rose said firefighters go into "these situations as a complete unknown."
"We go systematically, step by step," Rose said. "Our normal protocol is to make sure the public is safe and we’re safe when we are getting these samples."
The CAIR headquarters in Washington, D.C., was evacuated by dozens of police and emergency responders earlier Thursday after a "foreign" substance was received in a piece of mail. The FBI was also present.
Preliminary tests of the substance sent to the Washington office showed it was not dangerous and the FBI now has possession of the letter, which they will continue to test, the organization said on Twitter.
The office has received hate messages in the past. "We receive hate messages daily because of our advocacy on behalf of the American Muslim community," CAIR staff attorney Maha Sayed said in a post on Facebook. "It's frightening to experience the hate manifest itself to such a real level. This will not deter us from continuing to protect the civil rights and liberties of all Americans."
A spokesperson for CAIR's Sacramento Valley office said that facility remained opened despite the situation in Santa Clara.
Anti-Muslim sentiment is on the rise in the wake of the San Bernardino mass shooting. On Wednesday, a woman was caught on video making anti-Islamic slurs, then throwing coffee and an umbrella at a group of Muslim men praying at a Castro Valley park.