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The Initial Physical Aggressor Defense Under LC 3600(a)(7)

Labor Code § 3600(a)(7) establishes the initial physical aggressor defense. It explains that a claim is not compensable when the injury arises "out of an altercation in which the injured employee is the initial physical aggressor." That defense embodies the legislative intent to exclude from compensation those who introduce violence into the workplace.

The types of behavior that are barred under the statute were defined in the seminal case of Mathews v. WCAB (1972) 6 Cal. 3d 719, in which the Supreme Court explained that former LC 3600(g), now LC 3600(a)(7), applies when two conditions are present. One, the injury must "arise out of an altercation." Two, the injured employee must be the "initial physical aggressor" in the altercation.

It explained that an injury arises out of an altercation if it results from an exchange between two or more persons in an atmosphere of animosity and from a willingness to inflict bodily harm. It distinguished that from "horseplay" or "skylarking," neither of which involves animosity, although either can result in bodily harm.

As to the second condition, Mathews explained that battery was not necessary before one could be deemed the initial physical aggressor. That is, throwing the first punch in an altercation does not necessarily make a person the initial physical aggressor. The Supreme Court stated:

He who by physical conduct first places his opponent in reasonable fear of bodily harm is the "initial physical aggressor." His act need not actually cause physical harm; throwing a punch or shooting a gun is not necessary. Under appropriate circumstances, clenching a fist or aiming a gun may be sufficient to convey a real, present and apparent threat of physical injury.

So, to determine who is the initial physical aggressor, it must be determined: (1) whether a person engaged in a physical act; and (2) whether that physical act placed the opponent in fear of reasonable bodily harm. When the parties to the altercation are the sole witnesses, each typically will place full blame on the other. Whether the injured employee is the initial physical aggressor is a question of fact for the WCAB, and that often comes down to the credibility of witnesses.


For example, in Nosce v. United Building Contractors Inc., 2024 Cal. Wrk. Comp. P.D. LEXIS 53, the WCAB deferred to a WCJ's credibility findings and upheld a decision that an applicant’s injury was not barred by the initial physical aggressor defense under LC 3600(a)(7). In that case, the applicant and his co-worker worked as roofers, and the applicant was less experienced. When he made a mistake, the co-worker ordered him off the roof. The co-worker testified that the applicant breached his personal space, causing him fear of bodily harm. The applicant testified that the co-worker stepped toward him and started punching him. It was undisputed that the co-worker struck the applicant first.

The WCJ, and ultimately the WCAB, determined that the applicant was more credible than the co-worker. The WCJ made the credibility determination in part based on seeing the applicant and the co-worker in person. The applicant was described as shorter and heavier than the co-worker. He was described as "unfit/fat." But the co-worker was described as having muscle, being fit and "stronger and clearly capable of winning a physical altercation between the two men." The WCJ did not believe the co-worker was ever afraid of the applicant. The WCJ explained that her decision was supported by the investigative report from the sheriff's office, in which the deputy reported hearing the applicant and the co-worker arguing, and then seeing the co-worker approach the applicant, followed by punches. So the WCJ determined that the co-worker was not credible when he testified that the applicant got into his personal space and made him afraid.

The burden of proof in cases involving altercations rests with the employer, who must show that the applicant was the one who first engaged in physical conduct that a reasonable person would perceive to be real and present, and that posed a threat of bodily harm. The initial physical aggressor defense under LC 3600(a)(7) requires a comprehensive analysis of the altercation's circumstances, the behavior of the involved parties and a timely administrative response to contest claims effectively. If an employer denies a claim based on LC 3600(a)(7), it must be prepared to present testimony from the other person involved in the altercation or other evidence, such as witnesses or video evidence, to establish that the applicant was the initial physical aggressor. Then it must hope that the WCJ determines that the applicant is not credible on the issue.

For further discussion of the initial physical aggressor defense, review Sullivan on Comp Section 5.25 Initial Physical Aggressor.

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