Three are and have always been three components of e-liquid:
- propylene glycol (used in ice-cream soda etc)
- vegetable glycerin
- food flavoring
Besides proportions changing the only other variant is the type of flavoring. It's not actually too complicated.
And If one of those ingredients was suddenly tainted people using vaporizers would not be the only ones affected, of course.
All three of those elements are not usually vaporized and then inhaled in large quantities. Extrapolation from their effects when ingested is unlikely to apply in these cases.
Your conclusion does not follow from the evidence.
Not necessarily. The first two substances have been vaporized extensively in the past as fog juice. Modern fog fluids use (IIRC) a mix of different glycol formulations, but glycerin is no longer used in any commercial products due to health concerns.
> No Actor may be staged or choreographed within a distance from a specific product’s release point during the “wait” time listed on the product’s Time and Distance guidelines chart.
In Laymen's terms it says "Don't let the actor stand around breathing that shit any longer than necessary for the scene".
To me, that's very different from "inhale this shit directly into your lungs repeatedly multiple times a day".
Everyone is defending the ingredients as being safe but it's like defending water as being safe in when you have a patient who has steam related third degree burns.
My remarks were made in context where it is being claimed that “a new mystery ingredient” is cause for concern. I stated what ingredients are used as a point about how unlikely it would be for something out-of-the-blue to permeate the market.
In your document the Cat 4 exposure dose was stated to be 2.34 mg/L, a recent study[0] found that inhalation exposure at 0.442 mg/L resulted in slight irritation.
What's the exposure when vaping?
The document you link to actually avoids addressing Aggregate Exposure by stating there's insufficient information to draw any conclusions.
> "Since toxicological endpoints for risk assessment were not identified based on the available data, an aggregate risk assessment was not conducted for propylene glycol and dipropylene glycol."
Isn't Aggregate Exposure what we're concerned about with Vaping?
Additionally these studies all talk about aeroslized or nebulized pg, vaporizers are thermal in nature. Does heating pg matter?
The CDC is basically saying "We don't know what this shit does because no studies have ever exposed people to it in this manner. Until we know more you should probably not vape it".
[0] Dalton P, Soreth B, Maute C, Novaleski C, and Banton M (2018). "Lack of respiratory and ocular effects following acute propylene glycol exposure in healthy humans". Inhal. Toxicol. 30: 124–132.
Something just wasn't sitting with me about the document you shared [0] and toxicity categories [1], so I asked my partner, who is an environmental engineer, to explain it to me.
The EPA's toxicity categories [2] are determined by the amount of a substance that will kill you. So if it only takes 50mg/kg or less to kill you it's highly toxic, where as if it takes greater than 5000mg/kg to kill you it's considered non-toxic.
As my partner was explaining to me how to interpret the page, she furrowed her brow because she couldn't figure out how Dipropylene Glycol was Cat 4 and not Cat 3. Per the EPA guidelines the reported lethal levels for Dermal and Inhalation should make it Cat 3.
Further, the document says "Upon reviewing the available toxicity information, the Agency has concluded that there are no endpoints of concern for oral, dermal, or inhalation exposure to propylene glycol and dipropylene glycol." But if you look at the data provided, there is no inhalation exposure data for Propylene Glycol.
So why are we assuming PG is safe to inhale? And why is DG considered Cat 4 and not Cat 3? It's not entirely clear but my partner suspected lobbying which she said is quite common by industry groups like the American Chemistry Council.
I looked around and couldn't find anything specifically related to PG but the American Chemistry Council's Ethylene Glycol Ethers Panel petitions the EPA quite a bit to reclassify and remove reporting requirements. An example is their petition to remove reporting requirements for ethylene glycol monobutyl ether [3] which has similar toxicity categories to PG and DG. When you look at their section on Acute Toxicity, the rationale is not that it's safe but rather that it's unlikely to kill anyone the way it's used and stored in industry. So a lot of the justification that things are safe is based on how it's used. Vaping is a relatively new usage for PG.
When you look at the EPA's executive summary of propylene glycol [4] you can see that there's very little data around inhalation. The one thing I did find was a link to a Military Exposure Guidelines document [5] which indicates that Propylene Glycol exposure at 500 mg/kg (0.5 mg/l) was critically dangerous and resulted in convulsions in Monkeys. Wikipedia's article on propylene glycol [6] however references a study where subjects were exposed to 871 mg/m3 (0.8 mg/l) and only reported mild respiratory irritation. Keep in mind that your original document stated 2.4 m/l would kill you. So I'm inclined to believe that MEGs are closer to the truth than a Wikipedia study locked behind a pay wall.
The more I look into this, the more I see that there's very little research about the long term effects of exposure AND more importantly that much of the categorization, which predates vaping, is based on how it was being used at the time but does not take into account modern use cases.
My conclusion is that the CDC is right and people need to stop breathing this shit until we better understand it.
My remarks were made in context where it is being claimed that “a new mystery ingredient” is cause for concern. I stated what ingredients are used as a point about how unlikely it would be for something out-of-the-blue to permeate the market.
Just a sidenote, a lot of nebulized drugs also contain propylene glycol. I know it's not quite the same delivery mechanism as vaping, but it does end up in the lungs.
In addition to the delivery method being slightly different (because heat) the dosage is much higher.
The few studies out there, mostly related to theatrical fog, state that it causes irritation to mucus membranes. Is that what doctors are seeing in vaper's lungs?
- propylene glycol (used in ice-cream soda etc)
- vegetable glycerin
- food flavoring
Besides proportions changing the only other variant is the type of flavoring. It's not actually too complicated. And If one of those ingredients was suddenly tainted people using vaporizers would not be the only ones affected, of course.