The Maryland-National Capital Region Emergency Response System (MDERS) hosted a tabletop exercise (TTX) to evaluate the response efforts to an active assailant attack at the Washington Gas Rockville Plant. The exercise included participation from personnel representing Washington Gas, Montgomery County Police Department (MCPD), Rockville City Police Department (RCPD), Montgomery County Fire and Rescue Service (MCFRS), Montgomery County Office of Emergency Management and Homeland Security (MC OEMHS), City of Rockville, and Montgomery College (MC). Participants navigated the complex exercise scenario to cohesively manage and oversee response operations to mitigate the threats during an active assailant attack. The discussion yielded valuable insights for each agency and will help them all better prepare for these complex terrorist events.

Threats from nefarious actors are a constant threat throughout the country. Cyber and physical attacks can have debilitating impacts on communities, with far-reaching effects. This threat is heightened at critical infrastructure installations due to the essential functions they provide. This was evident three years ago in Maryland when an attempted terrorist act was thwarted, preventing two individuals from destroying electrical substations in the Baltimore region. It is against this backdrop that MDERS partnered with regional partners to systemically discuss an active assailant attack at the Washington Gas Rockville plant.

This exercise was the culmination of an exercise series with the Washington Gas Rockville Plant. The previous two exercises examined the coordination and response of plant personnel and first responders to a gas leak and fire at the facility. The lessons learned from those exercises guided planning efforts for this TTX.

The exercise workgroup, comprising subject matter experts (SMEs) from all participating agencies, continuously collaborated to plan each exercise. For this TTX, the workgroup identified the following goals:

• Evaluate Washington Gas’ emergency response operations, policies, and procedures.
• Evaluate the inter-agency response and coordination of Montgomery County Public Safety partners in response to an active assailant incident.
• Evaluate the response of MCPD and RCPD to an active assailant incident at a critical infrastructure facility.

These goals provided a framework for developing the exercise and served as the foundation for the subsequent evaluation.

The scenario for this exercise involved an evolution in suspicious actions occurring at the facility. Participants had to communicate to respond to an individual asking suspicious questions (e.g. Can this plant explode?), a trespassing incident, and two active assailants entering the facility. The workgroup created a master scenario events list (MSEL) to set a realistic progression and cadence for how such an event may unfold.

The ten exercise participants cohesively managed each aspect of the scenario, leveraging their expertise to minimize the theoretical harm in the scenario. The exercise concluded with a discussion portion and a hotwash that identified the strengths and areas for improvement during the exercise. All this information will be shared in an after-action report (AAR) with exercise participants.

These exercises and discussions are paramount for all agencies to revise existing plans and adapt to evolving threats. This TTX provided agencies with invaluable information, and MDERS will continue to partner with them to enhance response efforts in the Maryland-National Capital Region.

References

U.S. Department of Justice, U.S. Attorney’s Office, District of Maryland. (2025, February 3). White supremacist leader found guilty of conspiring to destroy regional power grid [Press release]. https://www.justice.gov/usao-md/pr/white-supremacist-leader-found-guilty-conspiring-destroy-regional-power-grid