SAN FRANCISCO (KGO) -- Shock waves from a New York bombing are being felt in the Bay Area with local law enforcement on high alert.
In San Francisco, more officers are already on patrol providing extra security for events like Oracle Open World.
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A police spokesman says they also depend on the public. "The best way to prevent anything like this from occurring, is really, you know we depend heavily on the public," San Francisco Police Ofc. Carlos Manfredi said.
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Extra patrols will be deployed in the city's high-foot traffic areas like the Embarcardero and Union Square just as a precaution.
According to a federal law enforcement official, residue from the Manhattan bomb is from a commonly available product called Tannerite.
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Some gun enthusiasts use it to create explosive for long range targets for shooting practice.
The FBI issued a warning about this material in 2013: "Criminals and extremists may actively be attempting to acquire explosive targets to obtain the immonium nitrate for use in the manufacture of improvised explosives."
The kits can be ordered online. They can even be bought in sporting goods stores in Sacramento.
In California, it's illegal to use these target kits, but it's not illegal to buy them.
Click here for more on the explosion in Manhattan.
Bay Area law enforcement on high alert after New York City explosion