Arizona Workers’ Compensation: Navigating the Law on Unexplained Falls

In Arizona workers’ compensation law, few scenarios are as misunderstood as the unexplained fall. When an employee falls at work but cannot identify a specific defect or cause, the claim’s success often hinges on a legal mechanism known as the Positional Risk Doctrine.

For workers' compensation attorneys, understanding how the law "fills the gap" when a cause is unknown is vital to securing benefits for injured clients.

1. The Neutral Risk Classification

The Arizona system categorizes risks into four origins: distinctly work-related, wholly personal, mixed, and neutral. An unexplained fall is considered a neutral risk because the cause is not identifiably work-related or personal.

Under the Positional Risk Doctrine, an injury is presumed to arise out of employment if it would not have occurred "but for" the fact that the conditions and obligations of the job placed the worker in the position where they were injured.

2. The Rebuttable Presumption: Circle K and Hypl

Arizona law provides a significant procedural advantage to claimants in these cases. If an unexplained fall occurs within the time and space limitations of employment (the "course"), there is a rebuttable presumption that the injury arose out of the employment.

• The Foundational Case: Circle K Store v. Industrial Commission established that when the cause of harm is unknown, the law "softens" the requirement for affirmative proof to ensure fairness to the worker.

• The Amnesia Extension: Historically, this was called the "unexplained death presumption" because the only witness was deceased. However, the court in Hypl v. Industrial Commission extended this to living claimants who, due to the trauma of the injury, suffer from amnesia or an inability to communicate.

  
  

3. Rebutting the Presumption: Personal Risks

Once the presumption is triggered, the burden of production shifts to the employer or carrier to prove the injury occurred due to a risk purely personal to the worker. If the defense can establish a personal cause, the fall is no longer "unexplained."

4. Unexplained vs. Idiopathic Falls

Attorneys must distinguish between unexplained falls (cause unknown) and idiopathic falls (cause is internal/personal, such as a seizure or spontaneous fainting).

• Idiopathic Falls: These are generally non-compensable because they stem from risks inherent in the worker's own physical condition.

• The Aggravation Exception: An idiopathic fall may become compensable if the employment aggravated the effects of the fall. For example, if a personal fainting spell causes a worker to fall from a height, into dangerous machinery, or near moving vehicles, the resulting injury is compensable due to the increased hazard of the workplace.