Tex. Civ. Prac. & Rem. Code 79.003
Liability: Disaster Assistance
An individual who, without compensation and at the request of an official, provides care, assistance, or advice during a disaster will not be held legally responsible for acting or failing to act. They can be held legally responsible if acting with extreme carelessness or intent to cause harm.
(a) Except in a case of reckless conduct or intentional, wilful, or wanton misconduct, a person is immune from civil liability for an act or omission that occurs in giving care, assistance, or advice with respect to the management of an incident: (1) that is a man-made or natural disaster that endangers or threatens to endanger individuals, property, or the environment; and (2) in which the care, assistance, or advice is provided at the request of an authorized representative of a local, state, or federal agency, including a fire department, police department, an emergency management agency, and a disaster response agency. (b) This section does not apply to a person giving care, assistance, or advice for or in expectation of compensation from or on behalf of the recipient of the care, assistance, or advice in excess of reimbursement for expenses incurred.