(a) All gas transported in transmission lines, and distribution mains operating at 125 psig (862 kPa) or more, except gas in route to storage fields via a transmission pipeline that transported gas without an odorant from that line before May 5, 1975, is to be adequately odorized in compliance with subdivision (c) of this section so as to render it readily detectable by the public and employees of the operator at all gas concentrations of one fifth of the lower explosive limit and above.
(b) All combustible gas transported in distribution lines, except as provided for in subdivision (a) of this section, and service laterals is to be adequately odorized in compliance with subdivision (c) of this section so as to render it readily detectable by the public and employees of the operator at all gas concentrations of one tenth of the lower explosive limit and above.
(c) In the concentrations at which it is used, the odorant in combustible gases must comply with the following requirements.
(1) The odorant may not be deleterious to persons, materials, or pipe.
(2) The products of combustion from the odorant may not be toxic when breathed nor may they be corrosive or harmful to those materials to which the products of combustion will be exposed.
(3) The odorant may not be soluble in water to an extent greater than 2.5 parts to 100 parts by weight.
(d) Odorization equipment must be designed and maintained so as to ensure the required odorant level in the gas under varying conditions. The equipment must be installed so that it does not cause a nuisance to nearby residents by the escape of odorant fumes.
(e) Each operator shall establish procedures to conduct periodic sampling of combustible gases to assure the proper concentration of odorant in accordance with this section. An appropriate record of all odorization practices shall be maintained.
(f) Every operator shall maintain records setting forth the types of odorizing equipment and odorants used, the ratios of odorant to gas, and the locations of odorization stations.