During the June 28, 1992, Landers and Big Bear earthquakes and resulting aftershocks, many masonry chimneys were hit hard. Building officials toured the damaged areas in an attempt to diagnose the problems. FINDINGS AND OBSERVATIONS Whether it was accidental or intentional, poor workmanship often was the factor that determined the damage a chimney sustained. Repeated instances of specific problems were observed among the damaged chimneys: Poor grout: Much of the grout or slushed mortar between the flues and the outer masonry units appeared to have partially set before being installed. Inadequate reinforcement: Several relatively new fireplaces and chimneys that completely collapsed amazingly lacked the code-required reinforcing steel. Inadequate anchors: Steel anchor straps, required at each floor and roof level, sometimes were missing but more often were either inadequately tied or not tied at all to the supporting structure. Missing ties: Although vertical reinforcing often was installed, lateral ties sometimes were omitted or spaced too far apart.