The SFPD arrested the man in the trailer, who was later identified as 32-year-old Thomas Siderio of Philadelphia. He was booked into jail on suspicion of distributing nitrous oxide and possessing nitrous oxide "with intent to ingest for toxication," police said.

A Philadelphia man was arrested on suspicion of possessing about 100 tanks of nitrous oxide outside Golden Gate Park, San Francisco police said.

Tens of thousands of Deadheads packed San Francisco's Golden Gate Park on Saturday for the second day of a three-day concert series honoring the Grateful Dead's 60th anniversary.