Back in the early 1950's, my BIL was clearing land with a CAT D4,,
This was before ROPS,, he was about 45 years old at the time.
A branch sprung off the blade, and hit him,,
When he realized what had happened, he spit out a BUNCH of teeth.
He got to live the rest of his life with a dental partial plate.
He used to spit that thing out and scare all of his grandchildren,,,
They welded a make-shift DIY ROPS on that dozer before it was operated again.
When they bought the Allis Chalmers HD-10, the first thing they did was add a ROPS,,,