Directs the Secretary of Transportation (DOT) to exempt from the requirement to obtain a hazardous material (hazmat) endorsement all class A commercial driver's license (CDL) holders who are custom harvesters, agricultural retailers, agricultural business employees, agricultural cooperative employees, or agricultural producers who operate a service vehicle with a fuel tank containing 3,785 liters (1,000) gallons or less of diesel fuel if the tank is clearly marked with a placard reading "Diesel Fuel."