By Alma Fausto | [email protected] | Orange County Register PUBLISHED: November 15, 2018 at 2:50 pm | UPDATED: November 15, 2018 at 2:52 pm A 38-year-old man was arrested after a large boom in a neighborhood led to the discovery of explosives and materials used to make them in the man’s home in unincorporated Tustin, authorities said. On Wednesday morning, Nov. 14, deputies were called after a resident of a condominium complex heard a loud explosion and found a piece of shrapnel in his backyard, sheriff’s spokeswoman Carrie Braun said on Thursday. Deputies talked to the resident’s neighbor in the complex, at 12720 Newport Ave., Kevin Sean Welch. They found pieces of a terra cotta, freestanding outdoor fireplace in Welch’s backyard. “Welch initially admitted to an accidental explosion resulting from an aerated can placed in the burning chiminea,” Braun said. “As deputies were investigating, they discovered items in plain sight that appeared to be explosive devices and fireworks.” Deputies called the Sheriff’s Hazardous Devices Squad and evacuated the condominium and four adjoining ones. The street surrounding the complex was closed during the investigation while investigators searched Welch’s home. Inside, they found a constructed pipe bomb, one that was partially complete, illegal fireworks and materials to make explosives, Braun said. Welch was arrested for possession of an explosive device near a residence, possessing materials with intent to explode, possessing fireworks without a permit, and sale of illegal fireworks. Welch’s bail was set at $1 million dollars. He remained in custody on Thursday.