“Local safety member” also includes any park ranger employed by a contracting agency who is a peace officer as defined in subdivision (b) of Section 830.31 of the Penal Code and whose primary responsibility is maintaining the peace and whose duties include law enforcement, emergency medical care first response, or fire suppression and prevention.

This section shall not apply to any contracting agency nor to the employees of a contracting agency until the agency elects to be subject to this section by amendment to its

contract with the board pursuant to Section 20474, or by express provision within its contract with the board.