A recurring debate in the academic and applied world is whether workplace committees and other forms of employee participation are substitutes or supplements to labor unions. This study addresses this question by examining the effect of workplace committees on the enforcement of public policies. A number of empirical studies demonstrate a positive relation between unionization and enforcement of government labor policies such as OSHA. Mandatory employee committees may similarly improve the implementation of public policies by acting as collective agents for employees in the workplace, thereby increasing the probability that workers will exercise rights granted them under labor regulations. The paper tests this hypothesized committee effect on the exercise of rights by examining the state of Oregon's experience with mandated safety and health committees. By comparing OSHA inspection records for the two years preceding and following the implementation of committee mandates in 1991, it shows that mandated committees significantly increase the differences between OSHA enforcement in union and nonunion workplaces following passage of committee mandates. As a result, the predominant effect of committees is that of a supplement rather than substitute for labor unions in the realm of public policies directed towards safety and health.