Ever since the most recent update to California’s Proposition 65 legislation, I’ve been getting this sort of panicked statement and question a lot:

“They just added styrene to Prop 65! I need to know if the polystyrene we’re buying from you is safe to use! We need a Proposition 65 statement and a residual styrene monomer statement! Hurry! Hurry!”

Whoa, whoa, whoa… calm down, friend. Take a few deep breaths, and let’s go through this together one step at a time.

First, it is true that the Office of Environmental Health Hazard Assessment (OEHHA) added styrene to the list of chemicals known to the state of California to cause cancer – better known as Proposition 65. However, there is a huge difference between what OEHHA is making a declaration on and what is being sold by M. Holland Company.

From the response to public comments on the listing of styrene, OEHHA made the following statement:

“OEHHA agrees that styrene is not the same as polystyrene and points out that polystyrene is not the subject of the proposed listing.”

So, the listing is for styrene monomer, not polystyrene resin.

“Ah,” you may say, “but the resin contains a certain amount of residual monomer, does it not, o regulatory guru?” Well, yes it does. But OEHHA addresses this, too, in their response to public comment:

“In its regulations of food packaging and food contact materials – including styrene and polystyrene – FDA [Food & Drug Administration – ed.] considers that these materials may contain substances or unreacted monomers that can migrate in trace amounts to food or beverages. FDA reviews safety data and sets regulatory specifications for these materials, including styrene and polystyrene, and requires sufficient scientific information to demonstrate that the intended uses of these materials are safe. Food contact materials meeting FDA’s standards are considered safe for food use.”

So, if the polystyrene resin you’re purchasing is FDA-compliant, it is a reasonable assumption that you do not need to worry about having a Proposition 65 warning on your product for styrene monomer. However, it remains the burden of the producer of a finished good to determine that the level of specific chemicals in the good does not exceed the “No Significant Risk Levels” (NSRL) that are established under Proposition 65.

One thing we cannot guarantee, however, is the ability to provide our customers with a residual monomer estimate for some resins. This is because some manufacturers still consider this to be a trade secret. Where we are able to make a declaration on behalf of our resin suppliers, we will do so.

Eagle-eyed readers of this blog may point out, “But there has been a Prop 65 statement in my Safety Data Sheets (SDS) for years!” – and they would be correct. This is because, prior to the April 22, 2016 listing of styrene, another chemical which is on the Prop 65 list has been used in the production of polystyrene resin – namely, ethylbenzene. It, too, is not over the NSRL amount which would require a warning.

However, Prop 65 is a “bounty” system – that is, anyone who knows a chemical is present can report it to OEHHA, leaving the “violator” to prove that the chemicals used are not above the risk levels. (As of 2006, the fines were $2,500 per violation per day, so you can see how this would quickly add up.) So, to avoid the legal nightmare, it is easier for the resin producer to simply make a statement that polystyrene is manufactured with a chemical (or, now, chemicals) known by the state of California to cause cancer… even though both ethylbenzene and residual styrene monomer are well below the NSRL limits.

Is there a specific regulatory subject you would like to see addressed in a future posting here in the blogosphere? E-mail me at: cthelen@mholland.com, and we’ll see what we can do for you.


If you would like to learn more about M. Holland and the plastic resin solutions we provide, submit a form and an M. Holland representative will follow-up with you.


If you would like to learn more about M. Holland and the plastic resin solutions we provide, submit a form and an M. Holland representative will follow-up with you.


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