(a) This section does not apply to a municipality to which Section 143.124 applies.
(b) A fire fighter employed by the municipality may not be required to submit to a polygraph examination as part of an internal investigation regarding the conduct of the fire fighter unless:
(1) the complainant submits to and passes a polygraph examination; or
(2) the fire fighter is ordered to take an examination under Subsection (f).
(c) Subsection (b) does not apply if the complainant is physically or mentally incapable of being polygraphed.
(d) For the purposes of this section, a fire fighter passes a polygraph examination if, in the opinion of the polygraph examiner, no deception is indicated in the examination regarding matters critical to the subject matter under investigation.
(e) The results of a polygraph examination that relate to the complaint under investigation are not admissible in a proceeding before the commission or a hearing examiner.
(f) The head of the fire department may order a fire fighter to submit to a polygraph examination if the fire department head:
(1) considers the circumstances to be extraordinary; or
(2) believes that the integrity of a fire fighter or the fire department is in question.