Massachusetts Department of Environmental Protection Finalizes Regulations to Incorporate Cumulative Impact Analysis Into Air Quality Permitting

On March 29, 2024, the Massachusetts Department of Environmental Protection (MassDEP) finalized regulations that require a cumulative impact analysis (CIA) when a facility is seeking a comprehensive plan approval (CPA) air quality permit. The CIA rulemaking applies to CPA applications submitted on or after July 1st, 2024.

CPA applicability criteria for new facilities are listed in 310 Code of Massachusetts Regulations (CMR) 7.02(5) and include the following:

• Emissions increase greater than 10 tons per year (tpy)
• Combustion units firing natural gas, distillate fuel oil, or propane greater than 40 million British thermal units per hour (MMBtu/hr)
• Incinerators
• Non-emergency engines operating more than 100 hours per year

A CIA is also required for any existing facility or emissions unit with a CPA that is proposing a facility-wide potential emissions increase of greater than one ton/year of criteria pollutants, hazardous air pollutants, or air toxics.

As described in 310 CMR 7.02(14)(a), an applicant is required to conduct a CIA when the facility or emissions unit is located within:

• An environmental justice (EJ) population
• One mile of an EJ population if the facility or emissions unit will not be a major source of air pollutants
• Five miles of an EJ population if the facility or emissions unit will be a major source of air pollutants

What must be done to comply with CIA requirements

Once a project is subject to a CIA, the project must:

• Provide advance notice, develop a project fact sheet, and attend a pre-application meeting with MassDEP
• Document measures taken to meaningfully engage the public
• Assess the baseline conditions of the EJ population
• And prepare an evaluation of the Project’s cumulative impacts

Advanced Notice and MassDEP Meetings

A project subject to the MassDEP CIA requirements must provide at least 60-day advance notice to MassDEP, the municipality where the project is located, and representatives of nearby EJ populations. The notice must include a project fact sheet that is translated into languages commonly spoken by the EJ population.

Once MassDEP has been notified, a meeting with the department must be held to discuss the public outreach and involvement measures and details of the CIA. MassDEP encourages a multi-faceted approach to public outreach which could include activities such as: community meetings, use of non-English media outlets, dissemination of the fact sheet, social media engagement, and/or establishment of local information repositories. MassDEP requires translation services to be a part of the public outreach and involvement measures.

During the pre-application meeting with MassDEP, they will request details on the approach used to assess existing community conditions as well as the approach that will be used to evaluate the Project’s cumulative impacts.

Assessing Existing Community Conditions

As part of the CIA, a project is required to assess the existing community conditions to characterize air quality and climate indicators, nearby regulated facilities, health, socioeconomic, and sensitive receptors within a 1-mile (or 5-mile) radius of the project. Thirty-three indicators are required to be reviewed as part of the CIA.

Assessing the Cumulative Impact of a Project

MassDEP’s CIA rule requires a project to conduct air dispersion modeling for criteria pollutants that will be used to compare to the National Ambient Air Quality Standards (NAAQS) and Massachusetts Ambient Air Quality Standards (MAAQS). An air modeling protocol must be prepared and submitted to MassDEP for review and approval. As part of this analysis, if a project includes significant new vehicle emissions, the vehicle emissions must be accounted for in the air dispersion modeling. Maps that show the modeled concentrations of criteria air pollutants in nearby environmental justice populations must be presented.

In addition, a project is required to characterize the risk of harm to health from air toxics using the Massachusetts Air Toxics Risk Screening Tool (MATRIST) which can be used to estimate cumulative air toxics risks from a project. MATRIST is a spreadsheet-based program that uses default air dispersion factors to assess the cancer and health risk for 237 air toxics at both the fence line and EJ populations. Depending on the proximity to other significant air pollution sources, MassDEP may require these additional sources to be included in MATRIST. As an alternative to using MATRIST, a project may prepare air dispersion modeling. However, this route requires a modeling protocol to be submitted to MassDEP for review and approval.

Cumulative risk from a project cannot exceed an excess lifetime cancer risk of 10 in a million or hazard index greater than one. The results of both the criteria pollutant modeling and air toxics risk screening must be described in the CIA, and maps provided that detail the results of the cancer and hazard index at the fence line and at the nearest EJ census block group.

Lastly, a project is required to evaluate and describe how the criteria pollutant and air toxics emissions could affect the existing environmental and public health conditions in nearby EJ populations. A project also needs to describe any mitigation measures that the project will implement to reduce or minimize the impacts from the project. MassDEP does not, however, mandate mitigation measures for most projects.

Once the CPA and CIA are submitted to MassDEP, a proposed decision is developed, and a formal 60-day public comment begins. Once the formal comment period closes, MassDEP will review the comments received and issue a final decision approving or denying the CPA.

What Does it Mean to You?

Massachusetts becomes the latest state to require consideration of cumulative impacts in air permit applications. The MassDEP CIA process requires an initial public outreach effort, documentation of the public outreach, an assessment of the baseline EJ community conditions and an analysis detailing the impacts both at the fence-line and on EJ populations. While not specifically requiring mitigation of impacts, the CIA report must document any mitigation proposed.

With the addition of CIA requirements the CPA permitting process is expected to take far longer as 60-day advance notice is required prior to submitting a CIA, and MassDEP will allow for a 60-day public comment on the proposed permitting decision which adds a minimum of 120 days to the permitting timeline. Another important note is that any facility with a current CPA that has a project related emissions increase of any air pollutant other than CO₂e of more than one ton will require a CIA.

If you have concerns about the potential implications of the MassDEP CIA rule or need help parsing through it, feel free to contact your ALL4 Project Manager or Joe Sabato. We’ll continue to follow how MassDEP implements the CIA requirements as more information becomes available. We can also help you evaluate permitting risks, from EJ concerns to regulatory issues, and assist in developing a strategy to make the permitting of your project as efficient as possible.