Section 144. (a) There shall be uniform natural gas leaks classification for all gas companies.

(b)(1) Gas companies shall assess a grade to all reported natural gas leaks based on the system provided in this section.

(2) A Grade 1 leak shall be a leak that represents an existing or probable hazard to persons or property. Grade 1 leaks require repair as immediately as possible and continuous action until the conditions are no longer hazardous. The gas company shall immediately schedule a completion of repairs and the condition shall be kept under continuous surveillance until the hazard or source of the leak is eliminated. Whenever appropriate and feasible, a gas company shall notify the fire department and chief law enforcement officer in each city or town where a Grade 1 leak is identified.

(3) A Grade 2 leak shall be a leak that is recognized as non-hazardous to persons or property at the time of detection, but justifies scheduled repair based on probable future hazard. The gas company shall repair Grade 2 leaks or replace the main within 12 months from the date the leak was classified. All Grade 2 leaks shall be reevaluated by a gas company at least once every 6 months until eliminated; provided, however, that the frequency of reevaluation shall be determined by the location and magnitude of the leakage condition.

(4) A Grade 3 leak shall be a leak that is recognized as non-hazardous to persons or property at the time of detection and can be reasonably expected to remain non-hazardous. The gas company shall reevaluate Grade 3 leaks during the next scheduled survey, or within 12 months from the date last evaluated, whichever occurs first, until the leak is eliminated or the main is replaced. A municipal or state public safety official may request a reevaluation of a Grade 3 leak prior to the next scheduled survey, or sooner than 12 months of the date last evaluated, if the official reasonably believes that the Grade 3 leak poses a threat to public safety.

(c) Upon the undertaking of a significant project on a public way exposing confirmed natural gas infrastructure, and with sufficient notice, a municipality or the commonwealth shall submit written notification of the project to a gas company. The gas company shall survey the project area for the presence of Grade 1 or Grade 2 leaks and grade 3 leaks identified as having a significant environmental impact and set repair and replacement schedules for all known or newly detected Grade 1 or Grade 2 leaks and grade 3 leaks identified as having a significant environmental impact. The gas company shall ensure that any shut off valve in the significant project area has a gate box installed upon it or a reasonable alternative that would otherwise ensure continued public safety and that any critical valve that has not been inspected and tested within the past 12 months is verified to be operational and accessible. The gas company shall provide the repair and replacement schedule of gas leaks to the municipality or the commonwealth.

(d) Gas companies shall prioritize any pipeline repairs required under this section for gas leaks detected within a school zone. For the purposes of this section, ''school zone'' shall mean on or within 50 feet of the real property comprising a public or private accredited preschool, accredited Head Start facility, elementary, vocational or secondary school.

(e) As part of the annual service quality standards report required by section 1I, each gas company shall report to the department the location of each Grade 1, Grade 2 and Grade 3 leak existing as of the date of the report, the date each Grade 1, Grade 2 and Grade 3 leak was classified and the dates of repairs performed on each Grade 1, Grade 2 and Grade 3 leak. A gas company shall specify any reclassification of previously identified leaks in its annual report. Gas leak information shall be made available to any municipal or state public safety official upon written request to the department.

(f) The department shall promulgate regulations necessary to implement the uniform natural gas leak classifications as specified in this section and shall oversee and monitor company response and reporting.