On March 29, 2024, the Massachusetts Department of Environmental Protection (MassDEP) promulgated cumulative impact analysis regulations. This new regulation requires projects seeking comprehensive plan approvals within a certain radius of environmental justice populations to conduct a cumulative impact analysis. MassDEP can deny a permit to such projects if the cumulative risk analysis reveals cancer and non-cancer risks exceeding specified thresholds. Massachusetts is the first state to require this form of analysis, which will apply to certain permit applications filed with MassDEP on or after July 1, 2024. The final regulations are very similar to the proposed regulations, which B&D analyzed last year.

The regulations include the following basic requirements for projects that must conduct a cumulative impact analysis:

• Evaluate 33 environmental, health, and socio-economic indicators relating to the community’s preexisting pollution and health burdens.
• Provide enhanced public outreach and involvement opportunities for environmental justice populations during the permitting process.
• Conduct increased air dispersion modeling of criteria air pollutants and toxic emissions.

MassDEP has released guidance and tools for conducting cumulative impact analyses, including a new mapping tool, indicator data, and air toxics risk screening tool.

A recent episode of B&D’s podcast Groundtruth explored the requirements of MassDEP’s cumulative impact analysis requirements and discussed other developments on cumulative impacts on the national scale. To discuss the final regulations, B&D associate Lauren Karam will moderate a Boston Bar Association panel on April 30, 2024.

Massachusetts’ new cumulative impact regulations demonstrate an increasing emphasis in both state and federal policy incorporating cumulative impact analysis into environmental regulatory decision-making.