The Texas Charitable Immunity Act of 1987 and the Federal Volunteer Protection Act of 1997 give physician volunteers limited immunity from liability when providing nonemergency care for certain organizations.
TMA White Paper: What you need to know about charitable immunity (July 2014)
The acts define a volunteer as a person who doesn't receive compensation in excess of expenses incurred. It covers practicing or retired physicians, physician assistants, registered nurses, vocational nurses, pharmacists, podiatrists, dentists, dental hygienists, and optometrists or therapeutic optometrists.
The Texas Department of State Health Services has compiled a summary (Sept. 2009) of the provisions of the charitable immunity laws.