 He told me, he says, Dad, I've already asked them a couple of times, and they told me, no, they're too expensive. Protective equipment like trench boxes are legally required by OSHA for any trench deeper than five feet. After Martin's death, OSHA fined his employer, Best Plumbing, LLC, nearly $19,000. The agency later reduced that to $11,000. Company owner Vincent Horvath declined to comment on the incident.