How dangerous IPA really is?


I would love to know what do you guys think about how dangerous IPA really is. My room is not well ventillated but still decent when I open the window a bit. What worries me the most is the risk of combustion of the fumes. I live in Canada so it is a bit cold, I thus need a warmer or my resin wont work if the window is open. I was wondering if the fumes from the IPA when I work with it to clean my tools, or when I transfill it in and out of the CW1 tank could get ignited by the warmer. I read it need 2% of IPA in the air to ignite but how much that really is? Would I pass out even before that threshold?


You will get varying replies on this question.

For me no real issue. I’ve been using the IPA for over 5 years in what should be my living room. Up until a year ago I also had a high end Epilog laser system running that had a powerful exhaust system so the air turned in the room quite often. Since I sold that I have no extra venting and see no difference.

Two years ago I went through extensive lung tests and thee where no issues. I asked the doctor about the IPA and he said there was no problem with using it.

You don’t want to be sticking your nose in the tank of course. I have run my 2 Form 2 units 14 hours a day with most prints being about 3 hours long. about 12 jobs a day run through the Form Wash unit. No real smell except when draining the freshly washed parts.

My wife is very susceptible to fumes and has countless allergies. She works in the same room basically every day. We had to move out of Florida because of her allergies. She was hospitalized a number of times over it. Not had any issues here in Indiana and none with my use of the Form Labs equipment.

Just one view of IPA usage. I also run stills to reuse the IPA. Of course I do that outside.


I guess its worth looking at a material safety data sheet and ask yourself.

Here is a link to one in the UK:

And one in the USA:

and in Canada:

Some interesting points from both:

Vapours may irritate the respiratory system and cause coughing, asthmatic breathing and breathlessness. Prolonged inhalation of high
concentrations may damage respiratory system. Central nervous system depression. Vapours may cause headache, fatigue, dizziness and nausea.

Heat may cause the containers to explode. Solvent vapours may form explosive mixtures with air. May travel considerable distance to
source of ignition and flash back. May ignite at high temperature. Vapours are heavier than air and may spread near ground to sources of

My own thoughts are that if someone wants to ignore the safety data sheet and they get away without any accidents then good luck to them - But its their own risk!! BTW - In Canada its classified as a hazardous substance (See extract below)

Just as a footnote - You need a minimum of 2% in air to form an explosive mixture, but that should not be confused with the amount to flash ignite, its got a flash point of only 12c so any sparks near it may ignite it

This article makes interesting reading: How to Work Safely with : OSH Answers

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Thanks both of you, very interesting response. What worries me the most, as pointed out by @Dxxxx is the possible travel of the fumes that can cause ignition of the mixture. My workspace is like 2mx2m and alright vented but not that well and I have a heater in a corner to keep the room above 18C for the resin to work fine. I am very worried because of that… I think I will try alternative like SimpleGreen, MeanGreen and ResinAway that has a very high flash point index and I will give you guys feedback if it’s worth the try. I don’t want to live my life in permanent stress of explosion in my room hehe…


IPA is relatively harmless unless you are exposed to high quantities. I looked for medical cases extensively back in the day. The only thing I could find was a patient hospitalized after putting IPA soaked paper towels on their skin daily, in which case it was getting into their body through their skin. That being said, mild temporary exposure to fumes may be ok, but I would not constantly expose myself under any conditions even at low doses.