Requirements for Facilities Converting from Oil to CNG/LNG

The conversions of facilities from oil to compressed or liquid natural gas may have implications with DEP licenses, permits or requirements. Facilities considering a conversion should contact Chris Swain, the Department’s Director of Innovation, who will walk through the specific circumstances, and work with facilities to determine what DEP requirements may be necessary. What follows is a very general list of possible interactions with the Department that will likely vary from facility to facility:

Bureau of Air Quality, Licensing Section LNG/CNG Regulatory Scope

The Licensing Section of the Bureau of Air Quality issues air emission licenses to minor and major sources that are above the licensing thresholds found in Chapters 115 and 140 of the department’s regulations. The summary below is for sources specifically switching to liquefied natural gas (LNG) or compressed natural gas (CNG) as a fuel source and for those new sources firing LNG/CNG.

The Licensing Section will be in communication with staff from the Bureau of Land and Water Quality, Division of Land Resource Regulation and the Bureau of Remediation and Waste Management as these projects move forward.

New Sources

New sources firing LNG/CNG are required to go through the air emission licensing process if emissions will be above the licensing thresholds. It is encouraged that discussions with air licensing staff occur prior to the submittal of the application.

Existing Sources

For those sources that already have an air emission license, allowing the firing of LNG/CNG requires an amendment to the air emission license. Contact with the assigned project manager or the Licensing Section Manager prior to submitting the application is strongly suggested. The project manager is listed on the bottom of the last page of the facility’s air emission license.

Helpful Links

Air License Applications and General Licensing Information:
DEP Rules Chapter 115 and Chapter 140

Bureau of Land and Water Quality, Division of Land Resource Regulation (DLRR) LNG/CNG Regulatory Scope

The DLRR administers the laws and regulations that relate to land development activities in Maine, including utility pipeline and terminal facilities.  Some of the applicable laws include the Site Location of Development Law (Site Law), the Stormwater Management Law, the Natural Resources Protection Act, and the Shoreland Zoning Act. Each of these laws has various thresholds or triggers, including proximity to protected natural resources (i.e., within 75 feet of a stream), amount of impervious or developed areas (i.e., > 3 acres of new impervious area requires a Site Law permit), or amount of impacts to resources (i.e., > 4,300 square feet of wetland fill requires a NRPA permit). There is no specific land development law relating to LNG/CNG developments.

New Developments

When a new LNG/CNG development is proposed, DLRR encourages applicants to meet with staff early in the planning and design process so that permitting questions may be answered in a timely manner.

Existing Developments or Redevelopments

When an existing site or use desires to switch fuel sources to LNG/CNG, DLRR will work with applicants to review what existing licenses may affect the site, and what new or modified licenses would be required. Depending on the scope, scale and location of the proposed modifications (i.e., new tank(s), new/modified impervious areas, wetland impacts, etc.), DLRR can offer guidance to applicants to assist in streamlining the permitting process.

In all LNG/CNG developments, DLRR staff will collaborate closely with staff in the Air and Remediation/Waste Management Bureaus to streamline the permitting process across all medias.

Bureau of Remediation and Waste Management LNG/CNG Regulatory Scope

Certain sections of 06-096 CMR 691 of the Department’s Rules for Underground Oil Storage Facilities would apply to owner and operators that are switching to LNG/CNG but would like to maintain their existing facility, retaining the ability to switch between fuels depending on economic conditions for the selected energy source. The Department’s Bureau of Remediation and Waste Management (BRWM) administers the rules for underground oil storage facilities.

Helpful Links

Further information and forms pertaining to underground oil storage tanks


Chris Swain will be the primary point of contact for conversion questions, and will facilitate compliance with applicable Department requirements. Chris can be reached by email at, by fax at (207) 287-2814, or by phone at O-(207) 287-7831, C-(207) 485-3852