One witness said, "It looks like a huge foam party gone bad."
At one point the foam was at least ten feet high, oozing out of the building.
VIDEO: Mountains of foam flood Santa Clara street
It looked so fun to one man that he got lost in it after asking police for permission to ride his bike through it.
"It just feels like soap," he said. Yeah it just feels like soap. Kind of smells like it too."
He wasn't entirely wrong, there is one difference: this foam is for putting out fires and it's made to coat the surface of liquids like gasoline.
Officials warned against getting the substance near your eyes, as it can cause irritation so they encouraged people to not go near the foam.
The spill enveloped an entire city block, oozing out of the San Jose airport's newest private jet hangar.
It was finished a year ago, just in time to host the teams that played in the Super Bowl.
A spokesperson for the company that runs it says no one was hurt when the fire suppression system suddenly activated, filling the empty space and street outside with foam.
Now that company is responsible for the cleanup.
Environmental group Baykeeper worries the coming rains could wash the foam into the Guadalupe River, which is home to a number of sensitive species, they say--and also drains into the Bay.
Stay with ABC7 News for more information on this developing story.