What is the main difference between a 'marking' and a 'label' on a hazmat package?

1. There is no difference; the terms are interchangeable
2. Markings provide the proper shipping name and UN number, while labels communicate the hazard class with symbols
3. Labels are used for domestic shipments, and markings are for international shipments
4. Markings are applied by the shipper, and labels are applied by the carrier