UPDATE: Suspicious Bottle on San Mateo Avenue Was Likely a Prank

San Mateo Avenue was shut down for more than two hours today while police investigated a suspicious bottle found near a gutter that was later determined to be probably nothing more than a mischievous prank.

Crews from the , South San Francisco Fire Department, San Mateo County bomb squad and San Mateo County Health Services were called out to secure the area and remove the bottle after someone called police at about 12:30pm to report the item found on the 400 block of San Mateo Avenue.

A hazardous materials crew diffused the substance in the bottle and determined that it was an unlabeled two-liter plastic soda bottle filled with muriatic acid.

"The quantity was so small  that it didn't do any damage," said  Cprl. Howard Hoyer.

Muriatic acid is a liquid used for cleaning, and Hoyer said someone probably left it there hoping the bottle would pop when it expanded.

Downtown business owners were told to stay inside while officers waited for the haz mat team to arrive. Some business owners closed down their shops and left while the area was under investigation, opting to sacrifice a few hours of sales over jeopardizing the safety of their businesses and customers.

Traffic also was blocked on San Mateo Avenue from Jenevein Avenue to Angus Avenue.

The block was re-opened at about 2:45pm.