California Firestop is a specialty firestopping and construction-safety contractor serving Southern California and Arizona. Its site states that it is certified as a UL Solutions Qualified Firestop Contractor and a Factory Mutual firestop contractor, and carries California licence number 991135. Work covers through-penetration firestopping, joints and head-of-wall conditions on commercial projects. It publishes offices at Oceanside, Corona and Tempe.