12 PPM Butane / Propane in MA

Currently working with a lab in MA where the PPM limit for solvents is 12. We have been struggling to get there consistently with our shatters and live products.

Any suggestions or tips on post processing to help us get under 12 consistently?


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Is there a regulatory requirement to test that low?


This says 1ppm, but that’s specific for Med I assume?

Yes, in MA the residual solvent PPM limit for both butane and propane is 12 ppm.

I’ve had good success using active pulling with the vac(non stop) and nitrogen sweeping on initial purges. We were able to successfully and repeatably get 0ppm in 48-60 hours using the sweep tech. It reduced enough time on our purge we were able to go a bit hotter with little/no difference in product. We would purge at 98-100F with nitrogen sweeps on every initial vacuum as well as each pull after flipping slabs(we flip every 12 hours).



Thank you sir! Will definitely give this a shot, and appreciate the spoon!

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Most welcome, DM me if you have any specific questions once you get rolling :call_me_hand:

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How anal is the person picking up samples. Just send the diamonds and purge em a lil extra before sending so you dont have to subject your essential oils to more degradation/distillation.

That’s why you see shitty etoh and rosin “diamonds”


My educated guess would be: Dry Scroll Pump w/a cold trap and resin trap? Run it for 30 mins out of every hour and flip every hour on the hour?


Run a DSP (dry scroll pump I hate typing that) the entire time.:octopus::thinking:

… Or

Start making rosin.:yum:

12ppm is kinda ridiculously low for butane and propane.

I think most other states allow 5000ppm for those


Are you doing this N2 sweep in a vac oven? are you also doing it in your recovery tank?

Id think doing this process of fill/evacuate while in the recovery tank would work fantastic and take less time than in your vac oven

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The sweep tek I’m reffering to is done in a vac oven. You could definitely experiment with a pre-sweep in the collection vessel, but it will make your extract much more difficult to harvest without the reduced viscosity the extra solvent provides. Would also make avoiding nucleation for shatter very difficult as well as the fact you lose the benefit of a vac pump pulling aggressively while sweeping.

I have heard of people using sweeping gasses across their collection vessel to recover more quickly though I have very little experience with that technique.


I would think 500ppm

Colorado is definitely 5000ppm

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CA, WA, and apparently CO are all at 5000 ppm. which I believe is based on OSHA work exposure standards

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Being under 800ppm for butane would work out but other than that it should be under 1,000ppm for isobutane and propane.

If we’re going by workplace exposure limits.

12ppm is pretty crazy. I believe the detection threshold is 10ppm. Some regulators in MA just didn’t want hydrocarbons all together. Have you tried:
1)Cold crash your oleoresin
2)Separate out THC-A from HTE. Ensure no THC-A crystals are in your HTE solution.
3)Grind THC-A to very fine powder. Use high-speed grinder, or mortar and pestle. Be thorough and make sure every single crystal is broken. Crystal can easily trap solvent inside their matrix and you’ll get something like 80ppm if you don’t break them up. If you opt for High Speed grinder, run it in short bursts to prevent overheating your media.
4) Purge THC-A powder under deep vacuum. The nitro sweep that @WolfeXtracts provided is excellent. if you don’t have Nitro in your lab, just go full vacuum, 50c for 48 hrs on your Isolate powder.
5) Gentle purge on HTE fraction. You’ll have to do optimization on this, or perhaps another provide this :spoon:.
6. Recombine and mix thoroughly. You’ll get a budder/pasty consistency, but it’ll pass without destroying or purging out all your volatiles.


Cause they’re lame af and old and like the hot dog water.


I’m looking-up stuff on my phone - kind clumsy, but found the reference in Exhibit 7b of the Mass CCC rules and regs. there12 ppm is crazy low, but it appears to be the limit for propose, butane and iso butane.


Same doc gives 5,000 to pentane and heptane.

Something is out of whack.