Thursday, April 9, 2009

Silica Desiccant Gel: Safe or Toxic?



I find these little packets of stuff in everything. This past weekend a few packets of it turned up in shoe boxes. I thought back to all the times I gave a kid their new shoes, in the box, and did not check to see if everything in the box was safe. Yikes!


So, now I'm curious to know if this stuff is really dangerous. The little packages almost always say "Do not eat" on them, but most kindergartners would not be able to read that, so I suppose I committed a grievous error. I went straight to Wikipedia to see what I could find out. According to Wikipedia, "Silica gel is a granular, highly porous form of silica made synthetically from sodium silicate. Despite its name, silica gel is a solid."
It's purpose is to absorb moisture, thereby retarding spoilage and damage caused by mold, mildew, fungus, etc. Some packaged desiccants contain fungicides and/or pesticides, making them dangerous for human consumption. According to Wikipedia, pure silica gel is unlikely to cause acute or chronic illness, yet is toxic. Further, Wiki's article stated that " Food grade desiccant should not include any poisons which would cause long-term harm to humans if consumed in the quantities normally included with the items of food." Somehow I wasn't terribly consoled by that statement, so I'll be steering clear of those little tagalongs in my pizza crust packages--food grade or not.


Reading on, I learned that Silica gel can irritate both the digestive and respiratory tracts, as well as the skin and eyes. Taking precautions is recommended. I'm picturing a face mask, safety goggles and gloves while shoe shopping and this does not present a pretty image.

That being scary enough, I further learned that some Silica beads include a moisture indicator called cobalt II chloride, which is toxic and considered to be carcinogenic. If your Silica beads are deep blue or pink, rather than white, they're likely doped with this dangerous stuff. Steer clear and don your safety gear.

Back in the days when we didn't worry about the safety of our foods, we used rice inside our salt and sugar shakers, to absorb excess moisture. This was a natural form of moisture absorption, and one of the safer forms of a desiccant. So why aren't they putting rice in those little packets, or simply dumping it into the shoe boxes? It wouldn't bother me to find a few grains of rice inside my shoes.

Desiccants are manufactured in little packets and included with many packaged products to maintain acceptable moisture levels. In addition to Silica gel, other commonly used desiccants are available, but may be used for various applications related to moisture level and food safety. I dug around in all of my shoe boxes and found the packets in the picture above. Nothing but Silica gel there.

Surprisingly, I found nothing about proper disposal of these little packages, so I'm creating my own set of rules. I started a new milk carton, labeled "Silica Desiccant Gel", to save for hazardous waste disposal. I can't say I'd want this stuff in the landfill, seeping into our groundwater. And that doesn't even begin to address the chemical reactions that could occur when these products react with others in the landfill. It's downright scary to imagine that this is going on right under our shoes and we're not noticing a potential safety issue. How many millions of these packets are there in our landfills?

Here is my new To Do List: Look for these packets in all boxes and shipping packages. Save them separately for a safer disposal than my curbside trash. Watch for other food grade desiccants in my packaged foods. What more can I learn?

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9 comments:

Jan said...

It does get overwhelming sometimes, all the things that are going on that we do unthinking that can harm the environment. It would be nice to reach manufactures along with the consumers of these products.

I may not comment offen, but I do pay attention and try to do the right thing.

I think your blog is excellent.

Carrie Boyko said...

Interesting point about reaching the manufacturers. I checked the packets I have collected in my milk carton, and surprise...no manufacturer's identification.

Thanks for the compliment. I am really enjoying this new adventure. The dog blog is coming along well also, despite it's much later start.

Iota said...

The MSDS on silica gel advises treatment with plenty of water if ingested. I don't think the gel is that toxic, it just has the the hazard of damaging you by absorbing liquid. As for the the cobalt risk, heavy metals are carcinogenic over time, but I suppose I'm a bit blase about the actual risk is small isolated instances. I'm a painter and use potentially dangerous pigments all the time, including lead, cobalt, cadmium, and mercury sulfate.

Carrie J. Boyko said...

Thanks, Iota, for adding some extra detail to this information. I do wish you well in your line of work--hope you are taking precautions to prevent over-exposure.

Anonymous said...

hi, thanks for the info, I would also like to know how to safely dispose of this, writing from sri lanka, and you can buy the blue stuff by the kilo... no mention of how to dispose of it safely either, and can't find much on the web. it's not clear how much exposure you'd need for a reasonable risk of something happening, this was the best I could find
http://msds.chem.ox.ac.uk/CO/cobalt_II_chloride.html

wishing you well

mssoh said...

hi Carrie,

Thanks for the great information in your blog, I've been so careless for not checking properly on the gifts to my children. I can't image what if they really eat the desiccant or play with them without my knowledge. I should spread out these useful information to benefits my neighbours and friends.

ALW said...

Hi, this is a most hilarious article, considering silica is the same chemical compound that makes up quartz, a natural mineral. Silica gel is essentially sand, and which is also used to make glass, hence the warning against possible skin, digestive irritation, you know, the kind of irritation you might get after a day at the beach. Yes, the indicator, if present, contains a toxic heavy metal. But if not, it is practically harmless and certainly not a disposal hazard.

huggyfee said...

ALW, I think the point is not that these are intrinsically dangerous - I think the point is that as these are so ubiquitous, multiply these tiny little things by the number of goods shipped by the whole world's population (as they do inevitably get thrown away) and you do have to wonder whether anyone has stopped to think about the potentialy environmental impact. E.g. if they absorb moisture, do they also absorb chemical compounds (example given being fertilizers etc.) from the manufacturing environments, hold these, and leach these back into the soil over time? Has anyone even done a study to evaluate their environmental and potential health impact?
This articles gives no real answers, doesn't scaremonger, it just poses questions, finds a big hole, and wonders what the responsible thing to do is as a consequence.
So this may make you laugh, as there are a million one other things that impact our lives, and this little packet seems trivial - but every now and then someone questions something trivial, and that sets someone else thinking, and eventually someone decides to find out - and maybe from this we find it's perfectly safe, or that it has enormous environmental impact potentially - so governments can then let people know to safely dispose of these things. Or maybe someone finds there are other dessicants, or manufacturing processes that could be used - or there's a hole in the market for environmentally friendly dessicants (a huge industry, surely) that uses well manufactured products (with no toxis components) and a sustainably managed wrapper (these things.
Taken from an eBay posting for these things:
Small sachets are manufactured as standard in a plain paper made from a blend of top grade manila hemp, cellulose and thermoplastic fibres.
So an environmentally friendly form of this could sell in the billions, and consumer pressure from responsible people would make such a manufacturer very rich, and the landfills safer.
So, this insignificant blog post may make you laugh. It may make someone else rich, change public perception, and this one thoughtful lady a little happier knowing she can safely dispose of her packed of dessicant with maybe a little green triangle on it, or just coloured light green so she knows it can be safely disposed of.
Don't underestimate the power of one person's thoughts. Every big thing starts with one person's musings.

@EduardoBeasley said...

Hi - Great blog post and a concern that is starting to be addressed by alternative solutions, where they can be used.
Silica gel is a synthetic amorphous silica not to be confused with crystalline silica (i.e. sand as per previous comment). In the activated form, silica gel acts as a desiccant and can cause a drying irritation of the mucous membranes and skin in cases of severe exposure. Cobalt and cobalt compounds are included on the IARC human carcinogens list. Cobalt chloride (as used as an indicator) can cause dermatitis and irritation of nasal passages and lungs.
The silica base is insoluble and nontoxic but where it contains an indicator (which is almost the default case) the Cobalt chloride may leach away if contacted with water.
So when this stuff ends up in landfill....

I am working on a project with a company that makes an environmentally friendly & compostable alternative to silica gel desiccants for preventing the development of mould growth on leather footwear and accessories. This is one of the main uses of silica gel desiccants so it's great to have a cleaner option!
The product they produce uses natural ingredients and attacks the mould spores that grow in damp & warm environments.
We are making inroads but a long way to go!

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