Ohio Rev. Code § 1563.32: Fencing of dangerous places - danger signs.

The mine foreman shall see that all dangerous places and old workings are properly fenced off, and proper dangersignal boards are hung on such fencing so that they may be plainly seen. He shall also travel all airways, and examine all the accessible openings to old workings as often as is necessary to insure their safety. All signs placed by the mine foreman under this section shall be marked "danger."

No person shall refuse or neglect to comply with this section.