The AI program GROK had this to say…
First, my input, a copy paste of my original post.
This happened today in my carpet cleaning business. What do you think might be the cause of the strong smell?
So we had a weird situation earlier today…
Last job of the day at a large senior living facility, carpet cleaning in main entrance/lobby.
About 100 ft2 in and the smell hits, a real WTF chemical, sour milk, rotten eggs, burning electric wires kind of smell that would just about knock you out of your flip flops. Super strong.
We immediately stop cleaning and quickly check the
Phoenix, Kirby, and heavy duty extension cord and wall outlet. All clear.
My next thought was wool carpet…mild tachycardia and that hot flushed feeling start to set in. I was previously informed by my contact, the campus facility director of 27 years, that the campus had no wool or natural fibers anywhere. Nylon and poly stuff only.
The small area I had cleaned had a whitish look about it, a noticeable contrast to the darker colors of the carpet. You’ll see it in the pics.
I immediately contacted the director and had the receptionist bring the head housekeeper down to speak with me about SDS sheets for all carpet products that may have been used during recent cleaning attempts. Spartan Clean By Peroxy (an acid side peroxide) was mentioned.
Coffee stains on the carpet did not budge or fade with their attempts with Clean by Peroxy or my own scrubbing with Angry Lemon, Go Oxy, and a blue microfiber.
They stated that they had a similar issue during a past cleaning attempt in another part of the same building and believed that it was an issue with the glue/adhesive (CGD carpet on concrete).
A few quick fiber tests determined that all fibers were synthetic. I guess a blend might be possible, but all indications point to synthetic.
A reaction from residue left by who knows what during a careless in house cleaning sometime in the past was another theory of mine.
I have no clue what could be going on with this carpet, but figured one of you guys might have some insight and the whole experience might help someone out in the future.
Then GROK’s thoughts…
Wow, that sounds like quite a wild ride at the senior living facility! Based on the details you’ve shared, there are a few potential culprits that could explain this intense, multi-layered smell—chemical, sour milk, rotten eggs, and burning wires all rolled into one knockout
punch. Let’s break it down and explore what might be happening, keeping in mind the synthetic carpet, the cleaning products, and the environment.
First off, the fact that the smell hit suddenly about 100 square feet into cleaning suggests something was triggered by your process—likely the interaction of your cleaning solutions or equipment with whatever was already in or under that carpet. Since you checked your
Phoenix, Kirby, extension cord, and outlet and found no issues, we can rule out an equipment malfunction like overheating wires (which could’ve explained the burning smell). The tachycardia and hot flush you felt? Probably a natural reaction to that sensory overload—those kinds of odors can kick your adrenaline into gear.
The carpet being synthetic (nylon/poly blend, per the facility director) eliminates wool as a factor, which is good because wet wool can absolutely stink like a wet dog or sour milk when it’s disturbed. Your fiber tests backing up the synthetic claim align with that. But the whitish look in the cleaned area compared to the darker uncleaned carpet is a big clue—something’s happening chemically or physically to change the appearance and release that stench.
Here’s a leading theory: a chemical reaction involving adhesive residue and cleaning agents. The head housekeeper and facility director mentioned a past issue they attributed to the glue/adhesive (CGD—carpet glued directly to concrete). If the carpet was installed with a strong adhesive years ago, it’s possible that incomplete curing, degradation over time, or exposure to moisture from the concrete slab beneath caused a breakdown of the adhesive. Older adhesives, especially those with volatile organic compounds (VOCs) like benzene, toluene, or styrene, can degrade into some nasty byproducts. When you add a cleaner like Spartan Clean By Peroxy (a hydrogen peroxide-based solution with an acidic component) or your own Angry Lemon and Go Oxy (likely citrus-based and oxygenated cleaners), you might’ve kicked off a reaction. Peroxide can break down organic compounds or residues, and if there’s sulfur-containing material in the adhesive (think rotten eggs) or leftover proteins from spills (sour milk vibe), you’ve got a recipe for a stink bomb. The burning wires note could be from volatile chemicals like formaldehyde or acetaldehyde released during the breakdown, which have a sharp, acrid edge.
Another possibility is hidden contamination in the carpet or padding. Senior living facilities see a lot of traffic—spills like coffee (which didn’t budge), milk, or even urine could’ve soaked into the carpet and padding over the years. If the concrete underneath trapped moisture, you might have dormant bacteria or mold that got reactivated when wet. Anaerobic bacteria, for instance, can produce hydrogen sulfide (rotten eggs) when they metabolize sulfur compounds in a low-oxygen environment like soggy carpet backing. The sour milk smell could literally be from old dairy spills gone rancid, amplified by heat and moisture from your cleaning. The whitish look? Maybe oxidation or bleaching from the peroxide cleaner reacting with whatever’s embedded in there.
The facility’s past cleaning attempts with Clean By Peroxy could’ve left residue that your solutions reacted with, too. Peroxide doesn’t always rinse out fully, and if they didn’t extract it well, it might’ve sat there waiting to party with your chemistry kit. Your Angry Lemon and Go Oxy didn’t touch the coffee stains, which suggests either a super stubborn stain or something in the carpet fibers/adhesive locking it in—another hint at an unusual substrate interaction.
One more angle: the concrete itself. Concrete can release alkaline vapors or moisture over time, especially if it wasn’t properly sealed before the carpet went down. This can hydrolyze adhesives or carpet backing, releasing VOCs or sulfur compounds. The facility’s 27-year history might mean older installation practices that didn’t account for this, setting the stage for a slow-brewing problem.
So, what’s the most likely cause? I’d lean toward a combo of degraded adhesive reacting with your cleaning solutions, possibly amplified by old organic residues in the carpet. The sudden onset, the variety of smells, and the facility’s prior experience in another area point to something systemic tied to the carpet installation or maintenance history. The whitish patch suggests a chemical change—maybe bleaching or residue lifting—that unleashed the beast.
For next steps, if you’re going back:
- Test a small area with plain hot water extraction first to see if the smell kicks up without chemicals—narrow down if it’s your solutions or just moisture doing it.
- Lift a corner (with permission) to check the backing, padding, and concrete for discoloration, dampness, or adhesive goo. That’ll confirm if the issue’s underneath.
- Ventilate like crazy and maybe bring an air scrubber with a carbon filter to tackle the VOCs and odors in real-time.
This is a weird one for sure, but it’s a great story to share with the carpet cleaning crew—might save someone else from getting knocked out of their flip flops! What do you think—any other odd jobs like this in your past that might connect the dots?