Tools are only as safe as the person using them, like the farm jack aka Hi-Lift. Here's a couple tips:
1. When winching or pulling someone from being stuck always throw a blanket or old coat or coveralls over the winch cable, strap, chain, whatever, about midway of the span. If it breaks the weight of the blanket or whatever causes it to drop, instead of fly though your windshield or back glass.
2. Always carry a sharp pocket knife where you can easily reach it with either hand. It is easy to get your shirt, hair or even hand stuck somewhere like an alternator, drill press or other spinning assembly (IRISH! LOL), and being able to cut yourself free may mean the difference between life and death, or being stuck somewhere by yourself for a long time till someone finds you.
3. Never refill a battery with a lit cigarette/cigar/doobie in your mouth, I've seen batteries explode spewing acid everywhere. Also always wear safety glasses, a respirator, and long sleeves/pants. A friend of mine I've known since 1st grade just had a lung biopsy because of lung damage from refilling batteries at a heavy machinery shop.
As a matter of fact when I am going to be working on my truck I grab at least a pair of safety glasses and put them on my hat in case I need them I wont be running around trying to find some. I also like to keep a pair of leather gloves handy too.