A hazmat incident causes a key interstate on-ramp to be shut down for 90 minutes while responders clear the scene, with no injuries and no leak from the hazmat packaging itself. Does this situation require National Response Center notification?

49 CFR 171.15(b)(1)(iv) (notice — major transportation artery closure, within 12 hours)

Drivers sometimes assume only injuries or spills require the emergency call, but a long traffic shutdown caused by a hazmat incident is its own independent federal trigger, so the notification duty exists even when nobody is hurt and nothing actually leaked.