(KRON) San Francisco Police Department officers patrolling the perimeter of Golden Gate Park during this weekend’s Grateful Dead’s 60th anniversary concert series found and seized roughly 100 nitrous oxide tanks and balloons prepared for suspected drug use.

Around 11 p.m. on Aug. 2, SFPD officers were in the area of Fulton Street and 35th Avenue when they came across an open trailer with a man inside. Officers approached the trailer and allegedly found numerous tanks filled with nitrous oxide.

Officers arrested 32-year-old Thomas Siderio of Philadelphia at the scene. Siderio was booked into the San Francisco County Jail for the distribution or dispensing of nitrous oxide and possession of nitrous oxide with the intent to ingest for intoxication. The case remains under investigation.

“Our officers will continue to patrol all areas of Golden Gate Park and the surrounding  neighborhoods,” SFPD said. “SFPD is dedicated to keeping everyone safe and will continue to ensure concert goers have a safe time while in our city.”