The National Labor Relations Board has no power to investigate an employer (or union) on its own. We cannot do our job unless people come forward, file charges, cooperate with NLRB investigations, and testify in NLRB hearings. It is unlawful for employers to discriminate against employees for helping the NLRB do its job.
Section 8(a)(4) of the Act makes it an unfair labor practice for an employer "to discharge or otherwise discriminate against an employee because he has filed charges or given testimony under this Act." (An employer that violates Section 8(a)(4) also derivatively violates Section 8(a)(1).) For example, you may not
- Discharge or otherwise discriminate against employees for announcing an intent to file a charge, providing information or giving sworn statements to a Board agent investigating a charge, refusing to disclose the identity of a charge-filing coworker, talking to coworkers about future testimony, or refusing to testify voluntarily on your behalf.
- Discharge or otherwise discriminate against employees because you suspect or believe, correctly or not, that they had filed or were about to file a charge.