The problem of selling chemicals to the general public



Most of the work I do is in multi family contexts and when I start a project with a new landlord I find that most of the tenants have been using aerosol pyrethrins, permethrin, or pyrethrin in dust format. I warn all my landlords about the dangers of those products and I have noticed their use decline drastically because the landlord warned the tenants. Once in a while we still see a can of that product and it is confiscated immediately and the tenant receives warning letters.

Aerosol pyrethrins are the worst of the three mentioned. Aerosol pyrethrins are legally sold for use on bed bugs and it does kill bed bugs on contact. The difficulty is that most bugs are hiding in cracks and crevices and it is unlikely that product would have much impact on population numbers. Actual studies have been done on this product with bed bugs being covered with a thin cover and the result was very few bugs died when the cover was treated. In field use we see that product chasing the bugs from suite to suite – sometimes by the hundreds. It is a very destructive product in the wrong hands.

Pyrethrin in dust format is slightly less destructive but still not a great product in inexpert hands. My own studies showed that over applying this product resulted in the bugs being repelled. And we often see this product used improperly with mounds of dust scattered on baseboards. The danger is that the bugs will avoid that pesticide and look for food in a safer spot – the next suite over. And then that suite repays the favour and the cycle continues.

More recently I noticed that the general public now has access to aerosol Permethrin at low concentrations. Permethrin is a second generation residual pyrethroid and is typically used by exterminators to kill bed bugs. The exterminator of course can mix at higher concentrations and is more effective but I have already shifted my use to the third generation Cyfluthrin as much as possible because of resistance issues. I do still use Permethrin in certain jobs as it has more permissive label directions.

The difficulty I have with Permethrin being used in inexpert hands is that even the best chemical will fail to deliver the goal if it is used inexpertly. Imagine an unskilled person being given the best carpentry tools in the world and being asked to build a house. The result would be a monstrosity. Similar problems occur in the exterminator world. But in the case of low concentration Permethrin we have a less effective tool being used in inexpert hands – a recipe for disaster.

If it were only the tenant that received the negative feed backs from his/her poor work I suppose I could live with that. But the problem is much bigger than poor results. The exterminator is currently limited to using only the pyrethroid class of chemicals which includes Permethrin. Best practice use of chemicals is to alternate different classes of chemicals on pests so that the difficulty of growing resistance is minimized. But with bed bugs the exterminator only has one class of chemical to use and it is already becoming less effective due to resistance. And now we have broad based inexpert applications of a low concentration pyrethroid increasing the growth of resistance to the only class of chemical that the exterminator can use. I don’t understand why we are doing that. It is very short sighted.


Interestingly enough I noticed that at least half of the products causing harm in multi family settings I address are actually sold by a large local exterminator with a large budget for advertising. I am sure that company knows the dangers, both short term and long term, but chooses to sell it anyways to make a profit. Perversely every can they sell increases the likelihood that they will be called for more work!! I suggest these products be banned from exterminator shelves in the same way that Canadian pharmacies can’t sell cigarettes.

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