San Bruno City Manager Connie Jackson told NBC Bay Area that there is no immediate danger to the public.
One YouTube employee tweeted, "Active shooter at YouTube HQ".
"It was very chaotic as you can imagine", San Bruno Police Department Chief Ed Barberini told reporters during a press conference at the scene.
"My stomach sinks with yet another active shooter alert", the Democrat tweeted.
The YouTube offices are located on the same suburban campus as Google.
"Was just briefed on the shooting at YouTube's headquarters in San Bruno, California", President Donald Trump tweeted. "The fire alarm went off so we started to evacuate and then people (started) running saying there was a shooter".
ATF officials said it will be responding to Tuesday's incident.
Space station the size of a bus to fall from the sky
It is assumed that China is unable to control or communicate with the station, though Chinese officials have not confirmed that. There is uncertainty with any spacecraft reentry and most of that comes down to the density of the upper atmosphere.
Synthetic cannabinoids usage linked several bleeding issues
According to the IDPH, synthetic cannabinoids are human-made, mind-altering chemicals that are sprayed on dried plant material. Unsafe and often unknown chemicals in fake weed commonly sold in convenience stores can lead to numerous health problems.
Toys 'R' Us liquidation sales delayed until Friday
A sign at the Toys R Us on Route 17 in Paramus announcing that liquidation sales were not taking place Thursday , March 22. Larian, with a net worth of $1 billion, according to Forbes , and associated investors personally pledged $200 million.
William Penn University to Host Annual Easter Egg Hunt
On Saturday, March 31, the Church of the Ascension in Westminster will host its second annual Special Needs Easter Egg Hunt. Friday at Wong Stadium, where there will be 30,000 plastic eggs with candy and prizes for youngsters to find.