5 CFR §550.906

1. (a)One or more of the conditions requisite for such payment ceases to exist;
2. (b)Safety precautions have reduced the element of hazard to a less than significant level of risk, consistent with generally accepted standards that may be applicable, such as those published by the Occupational Safety and Health Administration, Department of Labor; or
3. (c)Protective or mechanical devices have adequately alleviated physical discomfort or distress.