Ever wonder how those scratch and sniff stickers manage to pack a punch of aroma into what looks like ordinary paper? The technology behind it is deceptively clever, and has been used everywhere from children’s books to compact discs.
Most Scratch and Sniff stickers are simple nose-based novelties, though they’ve seen other uses as diagnostic tools, too. As Baltimore Gas and Electric discovered in 1987, though, these stickers can also cause a whole lot of hullabaloo. Let’s explore how this nifty technology works, and how it can go—somewhat amusingly—wrong.
The Science
At its heart, scratch and sniff technology involves the microencapsulation of tiny smellable particles, which are then impregnated into stickers or other paper products. Microscopic amounts of aromatic materiale are trapped inside gelatin or plastic capsules, and then stuck to paper. When you scratch the surface, these capsules rupture, releasing their aromatic cargo into the air. It’s an elegant feat of materials engineering, originally developed by Gale W. Matson. Working at 3M in the 1960s, he’d been intending to create a new kind of carbonless copy paper.
Scratch and Sniff stickers soon became a popular novelty in the 1970s. The catchy name was perfect—it told you everything you need to know. A children’s book named Little Bunny Follows His Nose was one of the first widespread applications. Released in 1971, it was entirely based around the whole scratch and sniff concept. Children could read along and scratch various illustrations of peaches, roses and pine needles to see what they smelled like. The book was reprinted multiple times, remaining in publication for over three decades.
Other popular media soon followed. Pop rock band The Raspberries put a scratch and sniff sticker on their album cover in 1972. Director John Waters would go on to release his 1981 film Polyester with an accompanying “Odorama” card, which featured multiple smells for viewers to sniff during the movie. The concept still resurfaces occasionally, though the gimmick is now well-worn. In 2010, Katy Perry’s Teenage Dream album smelled like cotton candy thanks to a scratch-and-sniff treatment on the Deluxe Edition, and King Gizzard & The Lizard Wizard put a similar touch on 2017’s Flying Microtonal Banana.
Best Intentions
Could scratch and sniff technology be put to more serious and noble uses? Enter Baltimore Gas and Electric Company. In 1987, the energy company had found the perfect way to educate customers about gas safety. The plan was foolproof—mail out 300,000 brochures with a scratch and sniff panel that would familiarize customers with the distinctive rotten-egg smell of mercaptan. That’s the sulfur compound added to natural gas to make leaks more easily detectable.
The brochures featured a red flame impregnated with scratch and sniff material. “Scratch this flame with your fingernail,” read the mailer. “Sniff it. . . . Let your family sniff it and be sure everyone recognizes the odor.”
The mailers were sent out with the best of intentions, in the pursuit of education and public safety. Unfortunately, the problem soon became apparent. Paper envelopes aren’t exactly hermetically sealed, and the stickers used were simply far too potent. The microencapsulated mercaptan scent was floating out of the envelopes before anyone could even get to the scratching part. Soon, the smell of gas was wafting out of these brochures all across Baltimore.
The result was exactly what you’d expect when 300,000 pieces of mail start simulating gas leaks all over town. Fire departments across the city were fielding a deluge of calls from concerned citizens who thought their houses were about to explode. Many hadn’t opened their mailers—they’d simply detected the smell and rang in the alarm.
The LA Times caught the story, and reported that Baltimore firefighters had responded to “at least half a dozen false alarms.” Officials noted that one call was attended by 27 firefighters and 8 pieces of equipment, all over a poorly-thought-out brochure. “I finally went up to this BG&E bill on the table, and the odor was so strong, you only had to be in the vicinity of it,” fire Capt. Raymond Devilbiss told the LA Times.
Spokesman for Baltimore Gas and Electric Company, John Metzger, would later describe the faux pas as “somewhat of an embarrassment.” The company quickly withdrew the remaining brochures, but the damage was done. They’d successfully demonstrated that their gas detection additive worked perfectly – perhaps a little too perfectly.
Funnily enough, this incident didn’t discourage other utilities from trying the same thing. Promo Printing Group in Florida produces a range of mercaptan scratch and sniff cards for various cities and gas utilities. You can get them from the National Energy Foundation, too. Utilities are still mailing them out, as well, and there’s at some anecdotal evidence on Reddit that this actually helped someone catch a gas leak in their own neighborhood.
The problem in the Baltimore case seems to be that the scratch and sniff stickers were simply too potent, or were otherwise releasing their scent when they shouldn’t have been. The incident serves as a reminder that even the simplest ideas can have unexpected consequences, especially when you’re literally mailing out thousands of artificial gas leaks. It’s a cautionary tale about the importance of exploring all possible failure modes–even the ones that seem absurd at first glance.
In the end, Baltimore Gas and Electric learned a valuable lesson about the potency of microencapsulation technology, and fire departments across Baltimore got some unexpected drill practice. As for the residents? They certainly didn’t forget what a gas leak smells like anytime soon. Indeed, though, the education campaign might have been pointless for some—the false alarm suggests many residents already knew the aroma quite well!
Man i remember these stickers, didnt knew this stuff was still around. Some of them purposefully smelled so bad it made you sick.
Oh the many times we put one under the teachers desk seconds before he/she came in ….
Nice to see these things got some good use these days.
Scratch-and-sniff websites. What would HaD smell like?
bar oil
It’s been tried before: https://en.wikipedia.org/wiki/ISmell
Rosin flux smoke (not that toxic RoHS stuff). Isopropyl alcohol. Whatever vaguely-petroleum smell solder paste has. Hot PLA.
And occasionally the acrid smell of magic smoke.
Perfecto! (And all so evocative…)
Or grandpa’s old garage with 50 years of spilled motor oil, leaded gasoline that leaked, and vintage Craftsman tool that outlasted Sears.
Plus B.O. and coffee breath.
Like solder and flux.
Ian of Dangerousprototypes add these stickers with this smell to the shipped out buspirate. I love it when opening its package and the smell of fresh solder welcomes you.
HaD would smell like a Sophomore dormatory at an engineering university.
They have been around long enough to get over the freshman bewilderment.
They turn in assignments, but never bother to spellheck or proofread them anymore.
They still aren’t experienced enough to leave the irrelevant subjects alone and do the actual assignment half the time.
It’s hard to be mad at the enthusiasm, but 3d printing wasn’t the subject of the assignment Timmy…
So…new paint, floor wax, clean(ish) sheets, new electronics, that-guy who doesn’t understand how to wear cologne, ozone, melted plastic, “the stain” that no one can identify but has its own backstory involving a chem student, and either laundry that should have been washed last week or chemical warfre strength fabric softener depending on proximity to the laundry room.
There will also occasionally be a VERY recognizable smell that makes no sense.
I was in a dorm briefly that smelled of fresh baked bread. Sometimes faintly. Sometimes so strongly it overpowered everything.
I walked around with the RA and we couldn’t figure out where it was coming from.
It was in the air every moment of the week I was there.
It was like someone was running a 24h commercial bakery out of their dorm room.
It was only faintly identifiable outside, so not a local business.
If it was a prank, it was a REALLY specific/obscure one.
If it was something off gassing, we couldn’t figure out what.
No one seemed to be sick, and I didn’t hear about them having to abandon the building for remediation after I left.
Dorms…
Spot on.
“never bother to spellheck or proofread” – It’s nice to know that Muphry hasn’t succumbed to old age.
Closet beer brewery.
Not exactly fresh bread, but yeasty smell.
When I was in living in dorms, it was against the rules to posses or drink vitamin ethanol on campus.
But not to make it. Not that it mattered at all.
Pro tip: Buy a case of cheap Champaign for each pony keg (e.g. two cases for a full keg). IIRC we mostly made hard cider, we were working on the ratio of our parties.
They did get better but were never really good.
Your a rat for involving the resident asshole.
That or the rarely seen female engineering student with a bad yeast infection.
Come to think of it, fat engineering student with yeast in his folds.
Statistically much more likely.
Fresh FR4 circuit board, stale beer, coffee, and Cheetos.
I wonder if they staggered the sticker distribution and very slowly shipped them to physically disperse locations over a number of years if the problem could have been avoided. Probably would have worked out cheaper as well.
Probably could have just put a foil wrapper around the card.
I remember some stickers had a pull tab you had to remove before you could get to the smell part.
Scratch-N-Sniff Pokemon cards!
All good until you got a Gastly and set up the fire alarm!
Or a Koffing and you wind up in the ER.
My wife works as a rural letter carrier for the USPS. Imagine what the Post Office smelled like…not the pleasant kind of “scented mail”.
Or they could have just gotten the concentration right. Mercaptan is used because we’re so sensitive to it that they only need to add a tiny amount to the gas lines for it to do it’s job.
Nobody in the production process for the stickers recognised that the odorant was orders of magnitude more potent than the usual compounds used in the process and so massively overdosed them.
I see creative writing is still alive and well at Reddit.
Interesting story about unintended consequences. Thanks for sharing! But I’m left wondering, in incidents like these, if “in the end” was really the end…
E.G. I wonder if there was an increase, thereafter, of actual leak-related incidents that led to disaster, due to the “boy who cried wolf” effect on the firefighters, their phone operators, and even the public?
My brother-in-law used to work for a county which was primarily rural. After ongoing issues with people from more urban areas moving into the county and then promptly complaining about the smell of the farms they moved next to, the county started producing educational brochures complete with scratch-n-sniff farm smells. IIRC the effort attracted national news coverage. Not sure how effective it was, though.
There was a Google Nose April Fool’s once
Way back when I was servicing appliances for a living, I got a service call for a gas leak around the customer’s gas clothes dryer. I smelled what very much smelled like the odorant used in natural gas, but I could not find any leak. Long story short, they had been painting in the next room, and the smell was caused by fumes that had reacted in the dryer’s pilot flame. Or something – the dryer hadn’t been used for a week, and it was the only gas appliance in that part of the house. The smell went away in a couple of days.
I wouldn’t compare the smell to the odorant in natural gas, but a gas stove absolutely reeks if you’ve been painting with solvent based paint in the same room as the stove is. Definitely either throws off the air/fuel ratio, or the solvents themselves stink when being burnt.
If, however, a vented system stinks after painting, it means that your vent is not really working well enough to suck away the combustion gases.
Reminds me of the story my comms teacher told me about the local (now Piedmont) office where they tossed some of those brochures that had some outdated information on them…apparently when they get rain soaked in an open top dumpster all of the odorant gets released All At Once. A gas leak called in on the gas company itself.
The movie Polyester was released in 1981 and was a minor hit, but in subsequent years it obtained cult movie status. As over the years the bulk of the audience would have never had access to Odorama cards I had always thought that Smell-O-Vision was an inside joke, especially given the over-the-top sniffing by the main character Francine Fishpaw and some of the smells that were supposedly present –
Flatulence
Skunk
Natural Gas!
Dirty Shoes
Also, as the movie takes place in Baltimore perhaps it was the subliminal trigger in 1987 for Baltimore Gas and Electric to use scratch and sniff cards.
A John Waters film is the worst possible choice for a scratch-and-sniff campaign (which is, obviously, why Waters did it.)
I remember the stinky variety of scratch n sniff of the 80s. One, the skunk sticker had smell that smelled like no one cleaned men’s locker room in years.w
Scratch and sniff Mars?
https://hackaday.com/2024/12/02/exploring-the-sounds-and-sights-of-alien-worlds/
I was working on the south coast of England a few years back when there was a big mercaptan leak… in northern France. People for 100 miles were getting whiffs of the stuff, absolutely incredible how powerful it is.
Here tetrahydrothiophene is used as an odorant in natural gas. When I was a student, there once was a party of the chemistry students. One of them thought it would be funny to bring a small vial of the stuff and release it in the venue. It wasn’t funny when everyone rushed out and the venue closed, fire brigade arrived, etc.
When I was a kid I had a copy of Charlie and the Chocolate Factory. The outside of the front cover was made to look like a golden ticket, and the inside of the cover had a scratch-and-sniff chocolate coating. The smell wasn’t quite right, but you’d be reading about this factory containing a river of chocolate, surrounded by a vaguely chocolatey smell. Good times.
CyberSniff 2000 ? In LSL7…
Somewhere someone has hermetically sealed copy of the scratch and sniff Hustler mag.
If you encounter it, run away!
I know the smell is most likely gone, but can’t risk it.
It smelled like the shithouse door from a tuna boat.
Fun fact, Mercaptan (ethanethiol) is also an off-flavor during the beer brewing process that they teach you about in Cicerone training. It is a defect that happens if the yeast dies off too quickly during brewing.
I had kinda hoped for a bit more of the HomeBrew HowTo from this article, but found this :
https://youtu.be/7ruSYfXTG9Q?si=6o-4lk-lhrg9B1ph
Enjoy!