Short answer: An employer generally cannot fire an employee because they got hurt on the job, filed a workers'-compensation claim, or threatened to sue or report a legal violation. Doing so is usually illegal retaliation under a mix of state workers'-comp laws and federal whistleblower protections. An injury or a complaint is not, by itself, a lawful reason to terminate someone. That said, an injured employee is not untouchable for unrelated reasons, and the rules vary significantly by state, so the details matter.
This is one of the most heavily litigated areas of employment law, and for good reason: retaliation claims are often easier for an employee to prove than the underlying injury or complaint, and they frequently attract plaintiff-side lawyers who work on contingency. Below is a plain-English walk through what is protected, what isn't, and the practical steps both sides should take.
The General Rule: At-Will Employment, With Big Exceptions
Most U.S. workers are employed "at will," which means either side can end the relationship at any time, for any reason or no reason — as long as the reason isn't illegal. Retaliation for exercising a legal right is one of the biggest illegal reasons. So while "I just don't want them here anymore" can be a lawful basis to let someone go in most states, "I'm letting them go because they filed a comp claim" is not.
The core legal concept is causation: did the protected activity (the injury claim, the complaint, the threat to sue) cause the firing? If the real reason was poor performance, a layoff, or misconduct that would have ended the job anyway, the termination may be lawful. If the protected activity was a motivating or determining factor, it likely is not.
Getting Hurt on the Job and Filing Workers' Comp
Workers' compensation is governed almost entirely by state law — there is no single federal workers'-comp statute for private-sector employees. Nearly every state prohibits employers from firing, demoting, or otherwise punishing a worker for filing a workers'-comp claim or for being injured on the job. This is often called a "workers'-comp retaliation" or "anti-retaliation" protection, and many states treat a violation as a serious claim with significant damages.
What this protection generally covers:
- Reporting a workplace injury to the employer.
- Filing or pursuing a workers'-comp claim, or testifying in someone else's claim.
- Hiring an attorney or otherwise asserting comp rights.
What it does not automatically do is guarantee the job forever. An injury does not shield an employee from a legitimate, unrelated termination — a documented pattern of misconduct, a genuine reduction in force, or an inability to perform essential job functions even with reasonable accommodation. The key is that the reason must be real, consistent, and not a pretext for punishing the injury.
Important overlap with disability law: If a workplace injury rises to the level of a disability, the federal Americans with Disabilities Act (ADA), enforced by the Equal Employment Opportunity Commission (EEOC), also applies to employers with 15 or more employees. The ADA requires employers to engage in an interactive process and provide reasonable accommodations (such as modified duty or leave) unless doing so causes undue hardship. Firing an injured worker instead of exploring accommodation can create ADA liability on top of any state workers'-comp claim. Many states have their own disability and fair-employment laws that cover smaller employers, so this varies by state.
The OSHA Angle: Reporting Injuries and Unsafe Conditions
The federal Occupational Safety and Health Act (OSH Act), enforced by the Occupational Safety and Health Administration (OSHA) within the U.S. Department of Labor, makes it illegal to retaliate against an employee for reporting a work-related injury or illness, or for raising a safety concern. Policies that automatically discipline workers for reporting injuries — or blanket post-injury drug-testing used to discourage reporting — can themselves violate OSHA's anti-retaliation rules.
An employee who believes they were punished for a safety report can file an OSHA whistleblower complaint, but the federal deadline for the core OSH Act provision is short — generally 30 days from the retaliatory act. Because OSHA administers many different whistleblower statutes with different deadlines, anyone considering this route should check the specific timeframe quickly rather than assume.
Threatening to Sue or Filing a Complaint
"Threatening to sue" is a broad phrase, and whether it's protected depends on what the employee is threatening to sue about.
When it is protected
If the threat or complaint involves a legally protected right, retaliation is generally illegal. Examples include:
- Discrimination or harassment based on race, color, religion, sex (including pregnancy, sexual orientation, and gender identity), or national origin — protected by Title VII of the Civil Rights Act; age 40+ under the Age Discrimination in Employment Act (ADEA); and disability under the ADA. All are enforced by the EEOC. Opposing discrimination or filing an EEOC charge is protected activity, even if the underlying complaint ultimately turns out to be wrong, as long as it was made in good faith.
- Unpaid wages or overtime under the Fair Labor Standards Act (FLSA), enforced by the U.S. Department of Labor, Wage and Hour Division. Complaining about unpaid overtime or minimum-wage violations is protected.
- Taking protected leave under the Family and Medical Leave Act (FMLA) for a serious health condition (including a serious work injury) at covered employers.
- Concerted activity — two or more employees discussing wages or working conditions — protected by the National Labor Relations Act (NLRA), enforced by the National Labor Relations Board, even in non-union workplaces.
- Equal Pay Act complaints about sex-based pay differences.
Many states add their own whistleblower statutes that protect employees who threaten to report or sue over violations of public policy, so this varies by state and is often broader than federal law.