A person with a commercial driver license that has a Class A combination vehicle classification is not required to obtain a hazardous materials endorsement pursuant to this chapter if the person is:
(1) Acting within the scope of the person's employment as an employee of a custom harvester operation; and
(2) Operating a service vehicle that is transporting diesel fuel in quantity of one thousand gallons or less and that is clearly marked with a flammable or combustible placard.