It wasn't SO bad once I was introduced to unfibered tar. But when I first started, the sadistic, stupid, fart breathed SOB purchasing agent for the company I was working for decided that it would be cheaper to buy fibered roofing tar to fill tub boxouts with. I used to dig holes in the ground and start fires in the holes with scrap lumber. Then put a couple of 2x4's across the top of the hole, and set the 5 gallon bucket of tar on top of it. Wait until it started getting really hot and runny, then grab it up and run into the apartment building to pour it into the tub boxouts. And then my boss would ***** at me for using so much tar.
I ran into that purchasing agent earlier this year, and I still hate him. 21 years later.
It used to be common practice, almost a code requirement, to use tar to seal the boxed out area in the concrete that was left open for the bath tub drains.