SAN FRANCISCO (KRON) – If you were wondering why fireworks exploded over the San Francisco Bay around 9:30 p.m. Oct. 19, you were not alone.

According to the Treasure Island Development Authority, the reason was “film activity” along the Avenue of the Palms along the western side of Treasure Island.

“Expect slight delays and fireworks over SF Bay associated with production,” according to a tweet.

The fireworks started on and off in short intervals over an hour period Wednesday evening.

The authority went on to state that there was no impact to Muni, and asked people to “allow extra time” if traveling on the avenue. There may be back-up filming Thursday, the authority concluded.

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The San Francisco Police Department did not know the cause when asked by KRON4 News.

“There was a fireworks show, do not know what it was for,” a spokesperson stated.