Gothamist
A non-profit newsroom, powered by WNYC.
Gothamist
Listen Live
News
Origin Of That Gross Subway Gunk Revealed
By
Ben Yakas
Published May 18, 2014
Modified May 18, 2014
Share
FacebookTwitterRedditEmail
Never miss a story
Email address
By submitting your information, you're agreeing to receive communications from New York Public Radio in accordance with our Terms .
By
Ben Yakas
Published May 18, 2014
Modified May 18, 2014
Share
FacebookTwitterRedditEmail
We rely on your support to make local news available to all
Make your contribution now and help Gothamist thrive in 2026. Donate today
Gothamist is funded by sponsors and member donations
The subways are a disgusting, unsanitary mass transit system coated in filth, epidermal flakes, and pus—but it's not all human detritus. Anyone who's ever averted their eyes to avoid awkward late night platform conversations with chatty drunks has probably noticed accumulations of spiderweb-like subway gunk on the floor. And it turns out that gunk ISN'T psychomagnotheric slime like we've always assumed it was!
Slate's Mark Vanhoenacker went on a quest to identify the gunk, which it turns out is a form of tar called mastic, which is used to seal tunnel structures. In the summer, the mastic sometimes melts, dripping from the roof onto the platform. MTA spokeswoman Marisa Baldeo said the molten tar is "nothing to be alarmed about," and certainly we've never witnessed anyone getting slimed by it before.
New subway tunnels use different kinds of sealants, so the mastic rorschach tests that adorn certain station's floors may become a relic of the past as more and more structures are repaired. Of course, judging by the enormity of the transit system and the long-term projects currently being worked on, we don't think we'll be seeing gunk-less floors anytime soon. And even if they did disappear, we're sure it would just be replaced with some suitably gross substitute.
Tagged
gunk
mastic
MTA
subway
subway gunk
tar
train
Ben Yakas
Ben Yakas is a former Gothamist reporter.
Read more
Gothamist is funded by sponsors and member donations
Gothamist is funded by sponsors and member donations
MORE news
Legionella found in Staten Island building's water system after 2 positive cases
Residents say several people living there are members of vulnerable populations.
By
Catalina Gonella
Published Oct 6, 2026 at 1:38 p.m. ET
Legal 'loophole' helps NY Gov. Kathy Hochul, Bruce Blakeman raise millions
In theory, New York's gubernatorial candidates can accept donations of up to $9,000. In practice, it’s way higher.
By
Jon Campbell
News
Legal 'loophole' helps NY Gov. Kathy Hochul, Bruce Blakeman raise millions
In theory, New York's gubernatorial candidates can accept donations of up to $9,000. In practice, it’s way higher.
By
Jon Campbell
Police identify 2 men wanted for stabbing an off-duty NYPD officer
By
Ben Feuerherd
NYC’s autumn foliage will be a fall feast this year
By
Rosemary Misdary
NY officials worry migrants will skip healthcare amid fed policy change
By
Caroline Lewis
Never miss a story
Catch up on the most important headlines with a roundup of essential NYC stories, delivered to your inbox daily.
Sign upEmail address
By submitting your information, you're agreeing to receive communications from New York Public Radio in accordance with our Terms .