Agents with the Food and Drug Administration's Office of Criminal Investigations search for nitrous oxide tanks during a joint operation dubbed "No Laughing Matter" with the Los Angeles County Sheriff's Department in Los Angeles Friday, March 22, 2013.
Authorities say they've arrested ten people so far in a crackdown on nitrous oxide for its illegal use as a recreational drug.
Los Angeles County Sheriff's spokesman Mike Parker says Friday's arrests were part of federal raids on 17 auto parts stores in Southern California last week.
Four were arrested by Food and Drug Administration agents on federal misdemeanor charges. Five others were arrested on weapons or narcotics charges.
Authorities seized more than 640 nitrous oxide tanks estimated at $20 million in street value. Authorities said more arrests could be expected.
Nitrous oxide is legally used by dentists for anesthesia, to pressurize whipped cream canisters and to speed up race cars. But authorities say its illegal use has spurred fatal car accidents, rapes and teen deaths.
Correction: An earlier version of this story stated that police had arrested nine individuals.