Germany introduced compulsory industrial accident insurance in 1884. The accident-insurance system compensated injured workers and survivors for losses, but initially failed to limit the growth of accident rates. We trace this failure to the 1884 law's faulty incentives and to an initial unwillingness to use the tools built into the law. The government regulator increasingly stressed rules that forced firms to adopt specific safety-enhancing innovations and practices. Econometric analysis shows that more consistent use of the rules and the limited incentives available under the law would have reduced industrial accidents earlier and more extensively.