Sec. 7. It shall be the duty of the owner, agent, superintendent, or other person having charge of such manufacturing establishment, or of any floor or part thereof, to report in writing to the Factory Inspector all accidents or injury done to any person in such factory, within forty-eight hours of the time of the accident, stating as fully as possible the extent and cause of such injury, and the place where the injured person has been sent, with such other information relative thereto as may be required by the Factory Inspector. The Factory Inspector or Assistant Factory Inspector and Deputy Factory Inspectors under the supervision of the Factory Inspector, are hereby authorized and empowered to fully investigate the causes of such accidents, and to require such precautions to be taken as will in their judgment prevent the recurrence of similar accidents. Sec. 8. It shall be the duty of the owner of any manufacturing establishment, or his agents, superintendent, or other person in charge of the same, to furnish and supply, or cause to be furnished and supplied therein, in the discretion of the Factory Inspector, or of the Assistant Factory Inspector, or of a Deputy Factory Inspector, unless disapproved by the Factory Inspector, where machinery is used, belt-shifters or other safe mechanical contrivances, for the purpose of throwing on or off belts or pulleys; and wherever possible machinery therein shall be provided with loose pulleys; all vats, pans, saws, planers, cogs, gearing, belting, shafting, set-screws, and machinery of every description therein shall be properly guarded, and no person shall remove or make ineffective any safeguard around or attached to any planer, saw, belting, shafting or other machinery, or around any vat or pan, while the same is in use, unless for the purpose of immediately making repairs thereto, and all such safeguards shall be promptly replaced. By attaching thereto a notice to that effect, the use of any machinery may be prohibited by the Factory Inspector, Assistant Factory Inspector, or by a Deputy Factory Inspector, unless such notice is disapproved by the Factory Inspector, should such machinery be regarded as dangerous. Such notice must be signed by the Inspector who issues it, and shall only be removed after the required safeguards are provided, and the unsafe or dangerous machine shall not be used in the mean time. Exhaust fans of sufficient power shall be provided for the purpose of carrying off dust from emery wheels and grindstones, and dust-creating machinery therein. No person under eighteen years of age and no woman under twenty-one years of age shall be allowed to clean machinery while in motion.