When should you ground a cargo tank being filled through an open filling hole?
Right! Ground before opening the filling hole and keep the ground until after closing it. 📖 p. 9-13
From Section 9 of the Iowa Commercial Driver's License Manual
Iowa CDL Hazardous Materials Practice Test
Who takes it: every CDL class (A, B and C), for the H endorsement.
Hauling placarded hazardous materials. 30 questions, 24 right to pass (80%).
Practice Hazardous Materials
- 10questions a round
- 2manual sections
Take the Hazardous Materials test
- 30questions
- 24correct to pass
- –no test taken yet
A Hazardous Materials question to try
Tap an answer to see if you’re right, and the page
Where it is in the Iowa Commercial Driver's License Manual
Iowa answers about this test
Practice material, not the official test: check every answer in your state's current handbook. Disclaimer · How the rounds work · DOT
All Iowa CDL tests
- General Knowledge
- Combination Vehicles
- Air Brakes
- Doubles and Triples
- Passenger
- School Bus
- Tank Vehicles
- Hazardous MaterialsYou're here
- Which tests do you need?Pick what you'll drive and get your Iowa CDL plan, in order.