By CBSLA Staff

IRVINE (CBSLA) – People in the Irvine area may hear explosions Wednesday morning.

The Orange County Sheriff’s Department Bomb Squad will detonate “explosive materials” which were seized over the July 4 holiday weekend.

The bomb squad will set off 20 pounds of material near Frank R. Bowerman Landfill between 10 a.m. and 11 a.m., the sheriff’s department reports. The explosives will be detonated in “shot holes” dug into the ground.

Those nearby may hear the loud explosions.

The O.C. Fire Authority and the O.C. Healthcare Agency is also helping coordinate the operation.

This comes after a botched explosion in a South Los Angeles neighborhood on June 30 which injured 17 people.

The L.A. Police Department had seized about 32,000 pounds of illegal fireworks from a nearby home and determined that some of it needed to be detonated on site because it was too dangerous to travel with. The LAPD Bomb Squad placed the explosives in a specialized armored truck designed for controlled detonations. However, what was supposed to be a controlled detonation turned into a massive explosion which damaged or destroyed 13 businesses, 22 residential properties and 37 vehicles.

On Monday, LAPD Chief Michel Moore admitted that a weight miscalculation likely lead to the explosion. The bomb squad incorrectly believed at the time that the net weight of explosives was 16.5 pounds. However, federal investigators later determined it to be over 42 pounds.

Several residents are still unable to return to their homes.