Imagine two Arab-American tanker drivers celebrating Muhammed with 8000 gallons of HAZMAT each, stopping in the bottom of the Holland tunnel, opening their valves and hatches.
That's one explosion that would be felt in DHS headquarters, Congress and the White house.
I'm no engineer, but I hope our tunnel operators have learned from
those tunnel fires in the Alps.
One documentary I saw said that the concrete roof had some melting due
to a semi-truck fire in one of the mountain tunnel.