Yes it is. Unless one guy has an infection that spreads through blood and other bodily fluids it's totally safe. Your immune system can handle these things.
The question should be stated differently but the short answer is no, blood pathogens and just about anything can be transferred from fighter to fighter and yes if a fighter has something and bleeds on you there is a chance you will get what they have.
How big of a chance depends on the circumstances and what it is.
"I fear no man, but Jim Harrison and Mike Stone are the two last men that I would wish to meet in an alley fight. Jim Harrison's fighting style is not flamboyant or spectacular, it's just simple and deadly!" - Bruce Lee sakurabushidokan.homestead.com