EXCEPTIONS.

(a) Section 52.061 does not:

(1) authorize a person who holds a license to carry a handgun under Subchapter H, Chapter 411, Government Code, who otherwise lawfully possesses a firearm, or who lawfully possesses ammunition to possess a firearm or ammunition on any property where the possession of a firearm or ammunition is prohibited by state or federal law; or

(2) apply to:

(A) a vehicle owned or leased by a public or private employer and used by an employee in the course and scope of the employee's employment, unless the employee is required to transport or store a firearm in the official discharge of the employee's duties;

(B) a school district;

(C) an open-enrollment charter school, as defined by Section 5.001, Education Code;

(D) a private school, as defined by Section 22.081, Education Code;

(E) property owned or controlled by a person, other than the employer, that is subject to a valid, unexpired oil, gas, or other mineral lease that contains a provision prohibiting the possession of firearms on the property; or

(F) property owned or leased by a chemical manufacturer or oil and gas refiner with an air authorization under Chapter 382, Health and Safety Code, and on which the primary business conducted is the manufacture, use, storage, or transportation of hazardous, combustible, or explosive materials, except in regard to an employee who holds a license to carry a handgun under Subchapter H, Chapter 411, Government Code, and who stores a firearm or ammunition the employee is authorized by law to possess in a locked, privately owned motor vehicle in a parking lot, parking garage, or other parking area the employer provides for employees that is outside of a secured and restricted area:

(i) that contains the physical plant;

(ii) that is not open to the public; and

(iii) the ingress into which is constantly monitored by security personnel.

(b) Section 52.061 does not prohibit an employer from prohibiting an employee who holds a license to carry a handgun under Subchapter H, Chapter 411, Government Code, or who otherwise lawfully possesses a firearm, from possessing a firearm the employee is otherwise authorized by law to possess on the premises of the employer's business. In this subsection, "premises" has the meaning assigned by Section 46.03, Penal Code.