https://www.nlrb.gov/strikes
Economic strikers defined. If the object of a strike is to obtain from the employer some economic concession such as higher wages, shorter hours, or better working conditions, the striking employees are called economic strikers.
They retain their status as employees and cannot be discharged, but they can be replaced by their employer. If the employer has hired bona fide permanent replacements who are filling the jobs of the economic strikers when the strikers apply unconditionally to go back to work, the strikers are not entitled to reinstatement at that time.
However, if the strikers do not obtain regular and substantially equivalent employment, they are entitled to be recalled to jobs for which they are qualified when openings in such jobs occur if they, or their bargaining representative, have made an unconditional request for their reinstatement.
Unfair labor practice strikers defined.Employees who strike to protest an unfair labor practice committed by their employer are called unfair labor practice strikers.
Such strikers can be neither discharged nor permanently replaced. When the strike ends, unfair labor practice strikers, absent serious misconduct on their part, are entitled to have their jobs back even if employees hired to do their work have to be discharged.
