A worker brought a giant (25 lb) ratchet wrench into the silo and dropped the 8 lb socket into the silo, where it fell a ways, bounced off something and pierced

A worker brought a giant (25 lb) ratchet wrench into the silo and dropped the 8 lb socket into the silo, where it fell a ways, bounced off something and pierced the 1st stage fuel tank. This wasn't an accident that was easy to get to happen, and I believe there's been nothing comparable, despite Titans being in service for 25 years, and refurbished and used as launch vehicles until 2003.