Not later than 30 days after the end of each month, a railroad carrier shall file a report with the Secretary of Transportation on all accidents and incidents resulting in injury or death to an individual or damage to equipment or a roadbed arising from the carrier’s operations during the month. The report shall be under oath and shall state the nature, cause, and circumstances of each reported accident or incident. If a railroad carrier assigns human error as a cause, the report shall include, at the option of each employee whose error is alleged, a statement by the employee explaining any factors the employee alleges contributed to the accident or incident.