I live in an industrial loft. My downstairs neighbor is a factory. When they're running, fumes come up through my bathroom into my apartment. It's serious problem.

The guy who lived here before me put in the pipes himself (he left behind the tools, even) and I'm guessing he did a slapdash job of sealing around them. I'd like to find the penetration that the fumes are coming through, make an airtight seal around that pipe, and live in peace and harmony with my downstairs neighbor once more.

Problem step 1: How do I figure out which penetration is leaking fumes? (Some of the penetrations, like the 3 water lines to the faucet, are closed off behind a boxy sink, too.)

Problem step 2: How do I seal it?

If you're paying rent, then this should not be your job. The landlord should be taking care of this. What type of fumes? Are they from a known carcinogen? Ask to see the MSDS sheet for whatever is producing the fumes. You have a right to know, if it can affect your health long-term.

check with your local fire department

being above a factory would require a 2 hour rated 'firestop' floor

there could NOT have been any permits pulled for this work

you are in deep do-do living in this unsafe manner w/o a valid certificate of occupancy

(any non-permitted alterations would have voided an existing c of o)

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638