According to Capital Journal on July 15th:

A small gas line was struck by an excavator working near the Stanley County High School parking lot in Fort Pierre on Wednesday at about 2 p.m.

Morris Equipment was excavating the old parking lot to replace it with a new asphalt surface when a piece of construction equipment struck a small gas line, according to the Stanley County Sheriff’s Office.

The scene was evacuated and Montana-Dakota Utilities workers shut off the line.

Stanley County Sheriff Office, Fort Pierre Fire Department and Montana-Dakota Utilities responded to the incident.