There were crashes of that magnatude in CART, but no fatalities, the Michigan 500 when back up cars were used to restart the race.

As for accidents that were as severe as to cause fatal injuries , Greg Moore was as bad as it gets , also in CART.It doesn't make a difference who the organization is, it happens.

It's auto racing , and unfortunately death happens. If we changed where we raced everytime there was a fatal accident, we'd be running only slot cars. From figure 8 racing to the quarter mile bull rings and everything in between people have been killed. You try to learn from their deaths on what to improve, but you can't stop, or else all is for naught.