The Los Angeles Police Department bomb squad erred when estimating by sight the amount of explosives contained in a cache of homemade fireworks that they then placed inside a containment vessel to detonate, resulting in a massive blast that injured officers and residents in June, federal investigators said in a report released Tuesday.

The vessel has a capacity of just 33 pounds of TNT, the Bureau of Alcohol, Tobacco, Firearm and Explosives said. Due to the bomb squad's inaccurate estimate, they thought they were putting slightly more than 10 pounds of explosives inside the vessel, the Daily News reports.

A squad member “stated no one weighed the material and no scale was used,” the ATF investigator wrote.

The explosion ripped through the vessel, launching large chunks of metal hundreds of feet away. At least 17 people, including officers at the scene, were injured. Dozens of buildings were damaged, leaving numerous residents homeless months later.

A group of residents have a lawsuit pending against the city.

The man who stockpiled the illegal fireworks now faces a decade in federal prison. Arturo Ceja III, 26, pleaded guilty to one count of transportation of explosives without a license, KNBC reports.

Police discovered about 32,000 pounds (16 tons) of commercial-grade fireworks on Ceja's property on June 30 after following up on a tip. Law enforcement also found 140 homemade fireworks and explosives-making components.