No person, firm or corporation shall furnish or supply any natural gas to any school or public building unless an odor producing liquid is injected into the gas mains before the gas enters the premises of such school or public building, so that a strong odor will be noticeable whenever a leakage of such natural gas exists.

(from Ch. 111 1/2, par. 3601)

(Source: Laws 1937, p. 487.)