Ask A Scientist Chemistry Archive

name         Peter W.
status       other
age          40s

Question -   My son (14) asked the origins of Petroleum Jelly, Vaseline,
we found that.
He then asked as it was petroleum / oil byproduct based, is it therefore
flammable / explosive?
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It is certainly quite flammable.

But it can only be explosive if it is mixed with approximately the right amount of oxygen or other oxidizer.
Sitting around in air does not push much oxygen into the jelly, so that is not explosive.
I think the jelly does not evaporate enough at room temperature to make explosive vapors over it.
But I cannot be sure.

At some slightly elevated temperature, a little above its "Flash Point" which is 50 degrees C in one MSDS I found,
the vapors in a deep or closed cup with petroleum jelly on the bottom may explode when ignited.
Drug-store Vaseline might have a slightly higher (safer) flash-point temperature.
Look for "flash point" in MSDS's on the web:
http://google.com,        Search[ "petroleum jelly" MSDS ]
http://www.ilpi.com/msds/index.html
http://msds.pdc.cornell.edu/msdssrch.asp
https://www.cms.anl.gov

Somehow making a spray of it (an "aerosol") is also a bad idea.

The fire of such jelly tends to float in the air just over the jelly for a little while.
A little like "Sterno", if you have ever watched that burn.
If you smear a little on a towel and light it, outdoors,
I think you will find the fire can be smothered fairly easily by throwing a second towel 
or blanket over it.
Wet  towel, even better.

But I would not wear it on my hair and smoke a cigarette.
Likewise, I would not smear it all over my pajamas and run a soldering iron.

And what about cooking?

Petroleum jelly is not a food item and should not be used for cooking purposes!

Jim Swenson
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