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Well, for one thing, you’d be eating a misnomer. Silica gel isn’t actually a gel, but a granular form of silicon dioxide (SiO2), a compound formed when silicon is oxidized. Silica gel is synthetic but SiO2 is also commonly found in nature (I trust you’ve heard of sand and quartz.)
But before we discuss the consequences of ingestion, here’s a quick history lesson. Silica gel has been around since at least the 1600s, but was a scientific curiosity until its absorbent properties were put to use during World War I in gas mask canisters. Walter Patrick, a chemistry professor at Johns Hopkins University, patented silica gel in 1919 and joined with Grace Davison, a Maryland-based chemical company, to further develop it. Davison began selling silica gel in 1923 but it didn’t take off until World War II.
Silica gel can absorb a lot of water—about a third of its weight—without undergoing a chemical reaction or changing shape. Even when they’re saturated, the granules stay dry to the touch and can be reused after heating at 250 °F for two hours. These properties make silica gel extremely useful for controlling moisture and humidity, and during the war it was used to keep medicine, military equipment and supplies dry.
Today it’s packaged with leather products, pepperoni, electronics and vitamin pills and used in museums and libraries to guard against rust, corrosion, tarnishing, mildew, mold and spoilage.
Risk Assessment
So what happens if you decide to defy the warning on the packet, defy the social norms of polite society and munch on a few granules? I hate to be anti-climactic, but most likely, the answer is …nothing! (Of course, there are some caveats, which we’ll get to in a minute.)
If you think about it, silica gel is basically man-made sand. It’s non-toxic and chemically non-reactive. People who have eaten anywhere from a few beads to a whole packet have reported no ill effects. If you’re curious, it’s reportedly almost tasteless, like licking a postage stamp.
Why the Skull & Crossbones?
Why the warnings, then? Well, silica gel isn’t completely dangerous, but it isn’t completely safe. Here are a few reasons the packets come with stern warnings:
Dehydration – Silica gel’s job is to absorb moisture, and it’s going to keep doing that as you digest it. You’d have to eat an awful lot of it to dehydrate yourself, but if you did, it would dry you out in no time.
Silicosis – This lung disease, also called Grinder’s disease and Potter’s rot, is caused by inhaling silica dust and causes symptoms like scarring and nodular lesions in the upper lobes of the lungs, shortness of breath, fever, and cyanosis (blue tinted skin).
Foreign vapors and toxic additives – You don’t know what the silica gel was exposed to between Point A and Point B. Eating a packet that came in a box of cockroach traps is definitely not recommended, but the gel could have absorbed other nasty stuff during manufacture or shipping and absorbed it. Sometimes, these things are added intentionally and packaged silica gel might have a bit of fungicide or pesticide added to it.
Another additive to watch out for is cobalt(II) chloride, which is toxic. This is added to the gel when a visible indication of absorption is needed. The cobalt(II) chloride makes the granules blue when they’re dry and turn pink when they’re saturated.
And the biggest reason? Lawsuits! – Even if the contents of a packet are plain old silica gel with no cobalt(II) chloride, and there’s no silica dust present and there aren’t enough granules to cause dehydration, companies have been sued over far stupider things. They’re just covering their butts.
If you’ve got a burning question that you’d like to see answered here, shoot me an email at flossymatt (at) gmail.com. Twitter users can also make nice with me and ask me questions there. Be sure to give me your name and location (and a link, if you want) so I can give you a little shout out.
There is a Seinfeld episode where Jerry drops a silica packet into some salsa and it is trouble for the woman who eats the salsa.
posted by Nicole on 10-5-2008 at 10:31 pm
The FIRST thing I thought of upon seeing the title of this article was Seinfeld, and it appears someone has already beaten me to it. Damn you, Nicole!
posted by monkey_b on 10-5-2008 at 11:42 pm
The silica gel packets would be easy to confuse with salt packers without the huge “do not eat” warnings.
posted by Sally Villarreal on 10-6-2008 at 1:20 am
You know what’s funny is that the packets are put in nearly every food product here in Japan, particularly in bread, to extend its shelf-life.
posted by Julie on 10-6-2008 at 2:48 am
It wasn’t Jerry, it was Kramer.
posted by ivan on 10-6-2008 at 6:34 am
I guess I can chill and stop screaming, “Don’t touch that. You could DIE!” to my children!
posted by Karen on 10-6-2008 at 7:06 am
I thought of Seinfeld too. But I also thought about the episode of The Simpsons where Homer eats the 40 year old Baking Soda from the back of the fridge. What would happen if you did that?
posted by Kevin on 10-6-2008 at 7:49 am
Well, Kevin, if I’m up on my Simpsons trivia, I believe you go out on an antacid trip. ;-)
posted by Roger on 10-6-2008 at 8:57 am
Roger,
Haha! But I meant in “real” life…
posted by Kevin on 10-6-2008 at 9:09 am
This makes me feel so much better, the other day I say my 11 month old baby playing with a packet of silica (not-)gel, and moving it towards his mouth. I nearly had a heart attack, I took it away and he cried.
I am still not going to let him play with it, but I doubt I will rush him straight to the ER like I thought I was going to have to if he ate it.
posted by Witty Nickname on 10-6-2008 at 9:19 am
the stuff is really great at drying out your electronics when they get wet!! i dropped my camera in the river and i put it in a bag of the stuff and left it on the dash of the car. i also dropped my cell phone in the toilet and did the same thing. both items work perfectly!! they sell it by the carton at places like target and walmart. i always have some on hand since i seem to have water issues.
posted by motorkitty on 10-6-2008 at 10:00 am
Yeah, my hubby dumped his pills into the damp sink, so I suggested he scoop em back into the bottle and added a silica gel pack. Okay, they were a little gritty, but what a $avings.
posted by Mare on 10-6-2008 at 10:33 am
My daughter ripped open a pack and ate some of the beads. We immediately called poison control and he told us not to worry, that it was more of a choking hazard than anything else. the poison control guy told us that in his training, he had to eat some silica gel beads so he would know what they tasted like …
posted by John C on 10-6-2008 at 1:22 pm
My brother swears by silica packets for recovering info from crashed hard drives. Apparently heat expansion can make your hard drive stop working. Or something. He puts the hard drive in a ziplock with a handful of silica packets and puts it in the freezer to cool it down; the silica absorbs the condensation inside the bag to prevent (further) damage to the hard drive. Then he puts it back in the machine to burn CDs of the info he wants to keep. He says it often works once or twice per hard drive for 20-30 minutes at a time, enough to save a decent amount of data.
I haven’t tried this myself, so don’t take my word for it: do some more research on this before you try it yourself!
posted by R on 10-6-2008 at 1:43 pm
I was always curious what would happen. The first thing I thought of was Seinfeld as well!
Anyway, we have packets and packets of the stuff where I work and they’re usually strewn about everywhere. At least now I know I was, uh, horribly paranoid for nearly no reason. (:
Also, this is unrelated to silica, but a guy I know dropped his phone in a pool and stuck it in a jar of rice and left it in the sun and it dried it out. Just thought I’d share that as well.
posted by Myleti on 10-7-2008 at 1:51 am