Chelsea Engine 4 was decommissioned in 1990, when the city went into receivership. Thirty-five years and many major fires later, the city has realized the need for a fourth engine company.

Engine Company 4 was returned to service in March 2025 as a second pumper out of Central Station. A 90-day trial was conducted in response to an increase in demand for emergency services and a high number of multiple-alarm fires experienced in Chelsea during 2024. The trial successfully demonstrated the value of the additional engine, showing improvements in response times, reliability, and overall effectiveness in fire suppression.

The city purchased a stock model 2024 Pierce Enforcer 1500/750 for the new company. It will continue to run out of Central until a new firehouse can be built in the area of Everett Ave / Produce Center.