Mass. Gen. Laws ch. 21K § 4
The department may, at the request of the local fire department or on its own authority, dispatch member departments of the hazardous materials mitigation emergency response plan to a site in the commonwealth for the purpose of conducting an emergency mitigation response for a hazardous material release or threat of release. During a declared emergency mitigation response action, the team leader shall have complete operational authority for hazardous materials team operations at all times. Once the team leader has determined that the imminent threat of harm from the hazardous materials release has been satisfactorily mitigated, the team leader shall thereafter notify the incident commander. The incident commander shall have authority over the emergency mitigation response site during a declared emergency mitigation response.
Any emergency mitigation response action taken by a member department under the hazardous materials mitigation emergency response plan shall be deemed to have been taken on behalf of the department and for the benefit of the commonwealth for the purpose of implementing the provisions of this chapter. Nothing in this chapter shall be construed in any manner to limit or abridge the right of the department of environmental protection to respond to a release or threat of release pursuant to chapter 21E.
Mass. Gen. Laws ch. 21K, § 4