Acrylic fumes, safety, MSDS

[Richard Rumancik]

One more point on the burning of acrylic. If you take a match and burn acrylic the composition of the smoke is different from what comes out when you laser it. When acrylic is burning the smoke is black + it smells different and worse . . Kim

I thought that I would respond to this as a separate thread. Kim, your point is well taken. Perhaps I should have found a better reference. I understand that burning acrylic in a fire will probably be more severe than laser cutting it, as laser cutting acrylic turns the plastic into a vapor and there is no smoke. Sometimes laser cutting can be similar to physical burning, if it cuts by decomposition, such as cutting fibreglass or polycarbonate, because you are effectively "torching" the material to cut it.

In my file I have a copy of a magazine article from Industrial Laser Systems magazine Sept 1998. Unfortunately, the archive is no longer available at their website. It states:

"One consideration with vaporization cutting is removal of the cut byproducts. In the case of Plexiglas, this is methyl methacrylate, a dangerous vapor when breathed, even in minute concentrations. Caution should be observed when cutting all non-metals, but especially polymers. It is prudent to exhaust vapors out of the plant where the concentration is reduced. A simple rule of thumb: if you can smell it, exhaust it."

I would go further and add that not all toxic vapors have a smell, so I would tend to exhaust when cutting any polymer, ablating paint, engraving composites like MDF, etc.

It is difficult to find conclusive evidence as to the toxicity of laser cutting a particular material. A lot of people on this forum suggest that users should get the MSDS for a material before cutting it. Rarely have I found the MSDS useful to decide whether or not to cut a material. The reason is that either it is very superficial, or lists so many toxic elements and health concerns that there is no real way for the average user to assess the risk.

When I did a quick search on acrylic, I found one MSDS that suggested that the most serious hazard for acrylic was cuts due to sharp edges on the sheet. Since you can't ingest sheet plastic or breathe it, they made it sound like it was inert. No comments on dust from sanding or polishing, or outgassing during heating for bending, laser cutting, sawing etc. So by looking at this MSDS you would have to assume it was 100% safe. If you don't process it in any way, it may well be inert.

I try to find information more directly related to laser cutting if possible. The plastic manufacturers often do not have much information. I have had them refer me back to the laser system manufacturers, who of course understandably decline to comment on any unusual materials. I have tried the Laser Institute of America, but so far have found very little information that can be applied to laser engravers. Many of their publication need to be purchased. NIOSH has some toxicity info at their website, but application of the information is difficult. They will tell you how many parts-per-million of methyl methacrylate will kill a rat, but this is not useful information to the laser fabricator as we want to know "safe" levels for people. Also, we do not have equipment to measure ppm of a chemical in the air.

There may be some materials that can be cut or marked without exhausting. I have never investigated marking marble or granite, for example. But in general I would also err on the side of caution.

[Joe Pelonio]

I have a couple of thoughts on acrylic. First, sawcut edges can be sharp enough to cut a finger, but I've never seen a sharp laser cut edge.

One day when cleaning my lenses I noticed a small screw sized hold on the inside back wall of my laser. I've probably been leaking some fumes into the room from it though it wasn't really noticeable, and it's been that way 4 years. Probably the force of the exhaust suction prevented much from going that way, but I blocked it off anyway.

There's more fume risk from manually flame polishing the edges with a torch than from exhausted laser cutting. That should be done in a well ventilated area.

[Belinda Barfield]

I have never investigated marking marble or granite, for example. But in general I would also err on the side of caution.

This is a very good point Richard. Most people who do not work with stone on a regular basis do not realize that much of the granite available purchase has been resin impregnated to enhance the color and structural stability of the stone, and many times chemical sealers have also been applied. Much of the marble that comes from China is dye impregnated. Getting an MSDS sheet for the resin or sealer from a granite supplier would be nearly impossible. In addition, any dust generated when laser cutting granite contains silica which is a serious health risk.

[William Johanson]

I work at my day job for a steel rule die maker. We currently run 4 large laser systems that have a fixed head and XY tables w/ servos. We have all 4 untis connected to a large exhaust unit with 2 large blowers on the roof. the vents are connected to the xy tables. We burn a large amount of Dieboard which is a very dense maple or birch plywood in various thicknesses. We also do a fair amount of laser cut parts in which acrylic and polycarbonate are very common. We had concerns about the exposure to the various chemicals being outgassed from the laser cutting process as you can definitely smell what you are cutting when you are in the room. We had a company come in to do an air quality sample. We did multiple tests on several materials. They placed little air quality samplers in variuos areas in the room including several directly mounted to the laser head, and several on the operator. One of these was worn by the operator all day cutting everything we could think of. I do not have the report with me at home but none of our tests came back even close to being borderline for dangerous levels to humans. The acrylic we cut is almost exclusively extruded and we are often looking for a flamed edge which smells horrible and strong but none of the tests came back as being dangerous. In fact we cut a piece of 2" thick delerin during this test that smelled so bad that we aborted the test and cleared the room. This test came out the worst but still not in dangerous levels. I will try to bring home a copy of these results and let you know some of the actual numbers in parts per million while cutting various materials. Obviously we all must be careful about what we are cutting and making sure we are being smart but this testing made me feel much better about being around lasers. Remember the systems I had these tests done with are open sided lasers and much more escapes into the working environment than with an enclosed system. Also these systems are very large up to 2000 watts which we are cutting up to a .050" kerf in 1" + materials all day long. If this environment is safe I dont think any of you who are using a relatively small enclosed unit with an exhaust system have much to worry about. But still know what you are cutting and pay attention to your environment. Obviously if you are getting ill, or your eyes are burning stop cutting. If you dont know what something is, dont burn it.

[Richard Rumancik]

William, thanks for the input.

I am not trying to create any undue alarm here, but just recommending prudence (like you and other members here.) The big problem with chemicals is that there are no "absolutes". They do tests on animals and try to extrapolate. The levels they set may or may not be truly safe; they use the best info and methods they have but something considered safe today can be considered a hazard tomorrow. It is next to impossible to predict long term exposure. Surprisingly, and luckily, the human body is pretty tolerant to a lot of very bad chemicals. But over time it sometimes catches up to us.

A recently opened a plastic bag for a power cord for a computer. There was a warning stating that the power cord contained chemicals known to the state of California to cause cancer. I don't know if there was lead in it or whether it was something in the plastic. They indicated that one should wash hands after handling. Does eveyone wash their hands after touching a power cord? Is this going overboard? They were taking the safe route I suppose, but we need to use common sense too. The downside of crying "wolf" too often is that people just start to ignore warnings.

If something smells so bad during cutting that people can't tolerate it, it is obviously a problem whether exposure levels are considered safe or not. You obviously did the right thing by stopping the Delrin test.

If we smell something or feel dizzy/get headaches/nausea etc it is a pretty strong indicator of a problem. But people's tolerance is different and unfortunately we sometimes get used to bad things.

As you said most the laser users on this forum use small enclosed lasers, so it tends to be easier to manage the fumes.

[Dan Hintz]

A recently opened a plastic bag for a power cord for a computer. There was a warning stating that the power cord contained chemicals known to the state of California to cause cancer. I don't know if there was lead in it or whether it was something in the plastic. They indicated that one should wash hands after handling.

Richard,

You will see this warning on a surprisingly large number of items... it comes from California's illogical eagerness to be overly dramatic about cancer-causing agents (among others). They jumped on the European Union's RoHS (Reduction of Hazardous Substances) agenda with a passion (even though it has been shown to prevent little), and is now pushing similar legislation through for any products manufactured or shipped into California.

In other words, there's nothing any more dangerous about that particular cord's materials than any cord you've ever plugged into your computer.

[Kim Vellore]

It is just abuse of proposition 65 that tried to keep toxic substances out of consumer products. It worked in a way to keep toxics out of kids toys, except some Chinese ones. You will not see this label in toys, if it does it will not sell. Almost all other consumer product manufacturers supplying to CA get away by not needing to test their products against toxic chemicals by putting this label. I even see this at work entrance door saying "This building contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm" and I still enter that building and work 9-12 hours every day.

Kim