I live in a 60 year old apartment building. There is a leak in my bathroom ceiling. I've been told the pipe from the toilet in the bathroom above needs to be replaced. I've also been told that my ceiling needs to be opened up to do this job. My questions would be:
Is this a big job?
How long does it take?
Is there any risk involved with the opening up of the ceiling as to breathing noxious chemicals or contaminants?
Is the pipe liable to contain urine and feces?

Thanks very much. :)

Til an Expert arrives.
Can't tell if large or small job, working with old plumbing is can be opening a Can of Worms.
It would probably be better working from your ceiling as it needs to be replaced anyway.
If it is supply water, could be Mold.
If it is sewer leak, we know what is present.
Good Luck

First I would remove the toilet upstairs and check out the wax ring. It may be causing the leak. Also, I would check for dripping angle stop, toilet tank and/or water supply. It may be dripping on the floor, water goes under the toilet and shows up on your ceiling. It can also be water from shower door or curtain that splashed on the floor and finds its way to your ceiling.

If none of the above, than you have to open up ceiling from your apartment and observe the source of the problem. Depending on what it is it may be couple of hours of work replacing cast iron fittings. Or it may be easy patch. It is hard to say w/o seeing it.

There are no materials containing toxic chemicals in materials inside your ceiling. So you should be fine with the work.

Make sure workers spray inside of your ceiling with mold-killing spray before they cover up. Also, the ceiling should stay open for couple of days to allow spilled water to dry.

Let us know what happened... good luck... Milo