It was never definitively proven but poorly designed software was considered to be at the heart of a helicopter crash that killed 25 people including almost all of the UK's top North Ireland intelligence experts:
http://en.wikipedia.org/wiki/1994_Scotland_RAF_Chinook_crash...Software controls everything from nuclear power stations to missles to dams to radiation therapy machines (where, again, software killed 3 people - http://en.wikipedia.org/wiki/Therac-25)
Proper software engineering is increasingly more important and, I'd posit, likely to become even more important than civil engineering for public safety as time goes on.