Oakland police arrested two men and confiscated $50,000 worth of fireworks from a home on Thursday, two days before the Fourth of July.
Police spent the morning hauling out at least 10 boxes of explosives from the home in the 1100 block of 82nd Avenue.
Spokeswoman Johnna Watson said the home was discovered as a special unit was doing a "longterm investigation" into illegal fireworks. The Alameda County Bomb Squad was sent to assist and detonate the fireworks at a sheriff's facility.
Fireworks are illegal in Oakland, as they are in many parts of the state and country. They are also dangerous.
In June, a 42-year-old man accidentally set off a massive amount of explosives in his Fairfield garage, and was taken to the hospital with severe burns and life-threatening injuries.
NBC Bay Area's Lisa Fernandez contributed to this report.