(a)No state commission or agency or county or municipal agency, including local emergency planning committees, incident management teams, citizen corps councils, citizen emergency response teams, medical reserve corps, fire protection districts, and volunteer fire, ambulance, or emergency service and rescue groups, nor their officers, officials, directors, employees, trainees, or volunteers, when engaged in planning, training, or response activities regarding a natural disaster, hazardous material release, public health emergency, or act of terrorism or the threat of any such disaster, release, emergency, or act, shall be liable for the death of or injury to any person or for the loss of or damage to property or the environment except for gross negligence or willful and wanton acts or omissions.