The fireworks bust was handled by the El Monte Police Department Special Investigation Team and is part of a special Fourth of July enforcement.
Police will not say where in downtown Los Angeles the fireworks were found, saying it could compromise an ongoing investigation, but did say the fireworks were being sold out of a garage. Police said no one has been arrested.
Fireworks of any kind are illegal within the city of Los Angeles.
"If you have the illegal fireworks, you can receive a citation, or based on the amount of illegal fireworks that you have, you can be arrested," said El Monte Police Det. Ralph Batres.
The city of El Monte allows the sale of fireworks, but the type of fireworks seized was not the safe variety.
The legal fireworks stands are in place and ready to open just before the Fourth of July holiday, but illegal fireworks are showing up in the area as well. Just last week, police in La Puente seized $500,000 worth of illegal fireworks. The found boxes stacked to the ceiling in several rooms inside a home. Two men were arrested.
"What people need to know is all this stuff can basically blow up," Batres said. "When the kids have this in their hand, anything can happen."
Possession of illegal fireworks could lead to a fine of $1,000 and a year in jail.
Police officials said the illegal fireworks will taken to a location in the mountains, where they will be destroyed.