It shall be unlawful for any person to injure, break or remove any part or portion of the sewer or of any sewer appliance or appurtenance, or to discharge into the sewer any inflammable gas, gasoline, oil or petroleum byproducts or any calcium products or residue therefrom, or any other matter which by chemical reaction shall in any way injure said sewer, or any part thereof, or become dangerous to health, life or property, or any liquid or any other material or substance which will evolve in inflammable gas when in contact with water, sewage or fire. Oil separators installed in any building where volatile fuels are used must not be connected directly with the sewer. (2016 Code)