## Facts

- Helen M. Rodriguez worked for the City of Brighton as a special-events coordinator and had an office in the basement of city hall.
- After briefly speaking with coworkers, Rodriguez began descending concrete stairs to return to her basement office and fell down the stairs.
- The stairs were dry and clear, and no coworker observed a trip, slip, or other apparent cause.
- Rodriguez showed no signs of illness or dizziness and reported no symptoms (e.g., headache, neck pain, dizziness, vision issues) before the fall.
- At the hospital, physicians discovered four unruptured brain aneurysms.
- At the workers’ compensation hearing, two physicians opined the aneurysms did not cause the fall; one physician suggested they did.
- The ALJ credited the two physicians, found the aneurysms did not cause the fall, and treated the fall as unexplained.

## Issues

1. Whether an unexplained fall at work satisfies the “arising out of” employment requirement under Colorado’s Workers’ Compensation Act, § 8-41-301(1)(c).
2. Under § 8-43-201(1), who bears the burden of proof to modify an issue determined by a general/final admission, summary order, or full order, and what is the burden?

## Decision

- The Colorado Supreme Court affirmed the court of appeals’ result that Rodriguez’s injury was compensable, but for different reasons.
- The court held that an unexplained fall is a neutral risk and can satisfy “arising out of” employment under Colorado’s positional (but-for) test.
- Applying that test, the court concluded Rodriguez’s fall arose out of employment because her job placed her on the stairway at the time of injury.
- The court held that a party seeking modification under § 8-43-201(1) must prove by a preponderance of the evidence that modification is warranted.
- The court rejected the court of appeals’ reasoning that uncertainty about cause cannot bar recovery if all potential causes would be compensable.

## Legal Principles

- Colorado classifies causes of workplace injury into employment risks, personal risks, and neutral risks.
- A truly unexplained fall is categorically a neutral risk (not personal), because if a personal condition caused the fall, the fall would be explained.
- A neutral-risk injury “arises out of” employment if it would not have occurred but for the conditions and obligations of employment placing the employee in the position where the injury occurred (positional/but-for test).
- Lack of proof of a specific workplace hazard does not defeat compensability when the injury results from a neutral risk and the positional/but-for test is satisfied.
- Under § 8-43-201(1), the party seeking to modify an issue determined by an admission or order bears the burden to prove, by a preponderance of the evidence, that modification should be made.

## Conclusion

The court held that an unexplained fall at work is a neutral-risk event and satisfies the “arising out of” requirement when employment placed the worker at the location of injury, and it clarified that any party seeking to modify an admitted or ordered determination under § 8-43-201(1) must justify the modification by a preponderance of the evidence.


City of Brighton v. Rodriguez, 318 P.3d 496 (Colo. 2014)