Michigan Compiled Laws, Chapter 324. Natural Resources and Environmental Protection § 324.20301

(a) “Hazardous material” means a chemical or other material which is or may become injurious to the public health, safety, or welfare, or to the environment.

(b) “Remedial action” means an activity to protect the public health, safety, welfare, or the environment and includes, but is not limited to, cleanup, removal, containment, or isolation of spills.

(c) “Spill” means any leaking, pumping, pouring, emptying, emitting, discharging, escaping, leaching, or disposing of a hazardous material in a quantity which is or may become injurious to the public health, safety, welfare, or to the environment.

(d) “Volunteer” means an individual who is designated as a volunteer by the public entity designated by the governor and is acting solely on behalf of that entity without remuneration beyond reimbursement for out-of-pocket expenses in connection with the assistance.

(e) “Waters of the state” means all groundwaters, lakes, rivers, streams, and other watercourses including the Great Lakes and their connecting waterways within the jurisdiction of the state.