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Methanol & Toxicity

As the person that said that I would like to try methanol, I
absolutely agree with Margaret and other respondents to the
Denatured Alcohol thread that methanol is poisonous. We should
educate ourselves about all of the toxic chemicals we use around the
studio. However, my preference is to use toxic chemicals when
necessary but to try to limit my exposure to safer levels. I want
to stress a disclaimer here: do not depend on the here
for your own safety…it is written to help you get started thinking
about the subject of toxicology rather than as the last word in the
subject. Read the instructions and be responsible for learning the
properties of what you are working with. With this in mind, I want
to provide a bit of about toxicity in general and about
methanol specifically:

Chronic Exposure & Chronic Effects: Refer to the effects repeated
long term exposure, usually to lower levels of a toxin.
Establishing cause-effect relationships for long term exposure is
difficult because of all of the different factors that can
contribute to the effects being studied. The diseases associated
with tobacco smoking are good examples of chronic effects. I was
not able to find much about the chronic effects of
methanol exposure. Material Safety Data Sheets often fail to
address chronic effects because of the expense and difficulty in
gathering sufficient statistical to eliminate other
enviornmental factors. Liver damage in plastics workers after long
term exposure to vinyl chloride is an example of the successful
study and regulation of a chronic environmental contaminant.

Acute Exposure & Effects: Refer to the effects of a single or short
term exposure where the effects can be observed during, or a short
time after exposure. Blindness or death after exposure to methanol
is an example of an acute effect. The response after a measured
dose of toxin is far easier to determine with studies of acute

LD50 This refers to the dose at which 50% of the subjects in the
experiment died. Since we don’t experment on humans, LD50
is usually for rats, rabbits, etc. LD50 is expressed in
weight of toxin per unit weight of subject. [Example: LD50 (for
some imaginary toxin) = .01 mg toxin/kg body weight.] Sometimes
after an accident, enough is collected that an LD50 can
be established for humans. LD50 refers to acute exposure, not
chronic exposure.

Irritant: I include this because of an error I made many years ago
that left me sick for several weeks…the label said irritant, I
though “So What?” Irritants can kill you. Example: Chlorine gas
is an irritant. Inhalation will kill you. Ferric chloride is an
irritant…don’t inhale irritant gases or dusts…

I am including some I found on the internet about acute
exposure to methanol. I did not collect the URLs of the sites that
I visitied but used a google search for terms like Methanol Toxicity
etc. Please do not depend on this to expose yourself to
Methanol…do your own research:

Skin Absorbtion rate: 0.192 mg/sq cm/minute (comment…skin
absorbtion rate can vary by a factor of 50 depending on where on the
body it is located. If I remember my college coursework correctly,
you should be more worried about spilling methanol in your lap than
the soles of your feet.) My reaction to a spill (usual disclaimer)
would be to get away from any flame, remove my contaminated clothing
and flush the affected area with water. Contact poision control. I
would not be personally concerned about a small quantity on my
fingers so long as it was rare and washed off immediately.

More on skin…lower doses cause dryness and cracking of skin…the
methanol, like many organic contaminants enters the body by breaking
down the lipids in the skin. Contamination of methanol by other
degreasing agents such as toluene (and I presume acetone) will cause
faster skin absorption. Organic contaminants are typically absorbed
faster on a second exposure than the first because the lipids in the
skin have already been compromised by the first exposure.

Lethal dose (ingested) 30 to 240 ml. (Keep in mind that
susceptablility varies between people depending on body weight and
many other factors. You absolutely don’t want to go for the new
record for sucseptablity.)

Has been observed to cause blindness: (ingested) 15 ml

density: 0.795 g/ml at 19 degrees C.

Permissable exposure limit (PEL, air) 200 ppm (please confirm this
if you use it) I personally would not want to expose myself to levels
anywhere near this limit on a chronic basis. Too little is known
about the chronic effects of this toxin.

Again…this is to get you thinking about doing your own research
into the chemicals you use then making your own decisions as the
whether and how you use them. I can’t stress too much that safe
acute levels are not necessarily safe chronic levels. How we limit
our exposure to chronic levels of toxins is a personal decision we
must all make. Chronic contaminants are all around us everywhere we
go. People tend to accept higher levels of voluntary exposure than
involuntary exposure. Example, most people would accept a higher
risk in their studio than from their drinking water or from air
pollution. Having studied many environmental risks in my
professional career, I am willing to accept small risks to continue
doing the work I love. (I better close this before I get into a
long discussion of risk/cost/benefit relationships). Remember, if
you don’t know what you are doing with chemicals, learn or don’t do

Howard Woods
Eagle Idaho

As others have mentioned earlier in this thread, methanol is
poisonous and must be handled with care.

An interesting fact that I don’t believe has been mentioned yet, is
that when methanol is burned it produces two harmless substances,
water and carbon dioxide.

I have been using methanol for years to mix my anti fire scale. I
believe it can be used very safely if it is handled with care in a
ventilated studio.

Milt Fischbein
Calgary Canada

Methanol: wood alcohol- if it was dangerous other than being
possibly explosive in vapor form, is used in denatured alcohol,.
toxic? i think not unless ya take it internally


    Methanol: wood alcohol- if it was dangerous other than being
possibly explosive in vapor form, is used in denatured alcohol,.
toxic? i think not unless ya take it internally 

It is most definitely toxic by inhalation and skin contact as well as
by drinking.

 From a MSDS for Methanol 

Routes of exposure
The substance can be absorbed into the body by inhalation and through
the skin, and by ingestion.

Inhalation risk
A harmful contamination of the air can be reached rather quickly on
evaporation of this substance at 20C.

Effects of short-term exposure
The substance irritates the eyes, the skin and the respiratory tract.
The substance may cause effects on the central nervous system,
resulting in loss of consciousness. Exposure may result in blindness
and death. The effects may be delayed. Medical observation is

Effects of long-term or repeated exposure
Repeated or prolonged contact with skin may cause dermatitis. The
substance may have effects on the central nervous system, resulting
in persistent or recurring headaches and impaired vision.

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160

Member of the Better Business Bureau

I’ve been following this thread and decided to add a few words.
There is another product , ethanol which in pure form diluted with
water is Vodka, commonly called grain alcohol. Ethanol works well
for lots of applications but must have a tax stamp if drinkable. To
avoid the taxing problem, ethanol is made unfit to drink or denatured
by the addition of methanol or wood alcohol.

The alcohol purchased in drug stores is USP or pharmaceutical grade.
The common product in hardware stores is ordinary industrial grade.

The impurities from burning are insignificant except to hard core
enviros. The combustion products are essentially water and carbon

Ringman, Methanol CAN be absorbed through your skin. And CAN blind
you. I am a chemist, and I am NOT kidding!


Margaret, How much methanol would it take to blind a person?

Regards J Morley Goldsmith/Laserwelding

How much methanol would it take to blind a person? 

Information I found on the internet (take it for what it’s worth) is
that cases of blindness have occurred with ingestion of as little as
15 mg. Remember that there is a difference in effects between
different routes of exposure…ingestion, inhalation, skin

Blindness is an acute effect that occurs when the levels in the
blood reach a certain level. In a shop exposure, that can happen
over a period of time when the intake rate from exposure exceeds the
normal elimination rate of the body.

I found no comparing toxicity from different routes of
exposure but the toxicity of some contaminants can vary considerably
with different routes of exposure. As far as acute effects go, I do
not believe there is much danger with the type of exposure we would
encounter at a jeweler’s bench unless there were a spill. Spills,
of course carry a great fire danger also. The large surface area of
a spill can greatly increase skin absorption or evaporation into the
air leading to inhalation exposure. One square foot of skin
exposure will absorb almost 1000 times as much per minute as one
square centimeter. The skin in the lap area (male) can absorb as
much as 50 times as fast as the soles of the feet.

You may want to follow this thread (still a relatively small thread)
back to last weekend where I discussed chronic health effects

I want to add one thing here…chronic effects may or may not have a
threshold exposure level of advere effects. That is, you may be
exposed to some things over time and never have any chances of long
term ill effects so long as you hold your exposure below a certain
level. With other contaminants very small damage with each exposure
accumulates into long term adverse effects. Methanol may be one of
the latter.

In researching this further on the internet, I found considerable
controversy regarding methanol metabolites from a popular artificial
sweetener. I also found that there is not much research about the
chronic effects of methanol. here is a link to one articl I found
using google terms “Chronic Methanol:”

Note that the “chronic” levels administered were probably nearly
high enough to cause acute blindness (I didn’t research those levels
in rats and have no idea what the rat’s elimination rate was. The
levels used in the study are certainly high enough to produce a risk
of acute blindness in humans)

I haven’t been too excited about long term effects because I keep
thinking if they existed and were serious, I would have heard about
them by now. (I thought the same thing as I was reading the first
news articles about asbestos back in the 1960’s)

I use methanol in my water torch and plan to contiune doing so; it
is mostly consumed by the flame. As I research this further, I am
becoming more convinced that if it is used for a boric acid dip,
proper ventilation is critical just as it makes good sense for
everything else we get exposed to around the studio. It is common
sense to always limit exposure to all contaminants.

Howard Woods
Eagle Idaho

Continue from:

Jim, What would you replace the long standing use of denatured
alcohol for wax applications in a class situation? I’ve been using
this compound For over 35 year. Maybe I should get my insides looked
into? In any event, what is your recommendation for a replacement?
Economy is an issue.

rp leaf