Helbut
I think there is an impossible fatal crash in formula 1.
The more uninformed F1 fans were saying that also in 2014, and look what tragically happened there.
Fact is when modern F1 car's can reach 230+ mph (370+ kph), serious or fatal crash can happen, however small this chance appears for some.
Helbut
In Australia in 1991, nothing dangerous happened for 14 laps.
Actually, from having watched the 1991 Australian Grand Prix, the first dangerous situation, in my opinion, occured on lap 6, when Larini and Alesi's cars were sideways across the track, creating a 'wedge' on the track. Alesi's car was also parked partly on the racing line. Not dangerous enough I guess for you.
The main difference though between 1991 and 2021 is the downforce levels of the cars. The modern F1 cars produce much more downforce, and this results in much more spray and mist from each car. This was the main concern, as you do not know for certain what lies ahead after 50 metres visibility. Clear road, or a slow or stationary car, you can not be certain.