Styrene, Polystyrene Foodservice Packaging and Prop 65 Q & A

On April 22, 2016, the California Office of Environmental Health Hazard Assessment (OEHHA) issued a Notice of Intent to list the substance styrene on California’s Proposition 65 list. Below you will find information on Prop 65, styrene and the safety of polystyrene foodservice packaging.

Q: What is styrene?

A. Styrene occurs naturally in many foods and beverages. Its chemical structure is similar to cinnamic aldehyde, the chemical component that creates cinnamon’s flavor. Styrene also is used as a building block to manufacture many materials (such as polystyrene) used to make automobiles, auto booster seats, electronics, boats, recreational vehicles, bicycle helmets, toys and countless other consumer products.

Q: What is polystyrene?

A. Polystyrene is a type of plastic used to make a variety of consumer products, such as appliances, CD cases, computer housings, petri dishes, foam insulation and foodservice packaging. It is made by joining together (polymerizing) many styrene monomer units, and it is used as both a solid and a foam material. Its largest use is packaging, including foam cushioning for shipping delicate electronics and a wide variety of food and foodservice packaging, such as drinking cups, egg cartons, plates and bowls, take-out containers and cutlery.

Q: So styrene and polystyrene are different?

A. Yes. Polystyrene and styrene are different substances with different characteristics. The U.S. National Institutes of Environmental Health Sciences (NIEHS) in June 2011 noted: “Styrene should not be confused with polystyrene (foam)*” and “styrene, a liquid, is used to make polystyrene, which is a solid plastic.”

Q: What is California Proposition 65?

A: Proposition 65 (“Prop 65”) is a California law (California’s Safe Drinking Water and Toxic Enforcement Act of 1986) that requires the state to create a list of substances that it believes have certain toxicological characteristics. The list includes substances that occur naturally in all manner of foods and that occur naturally in people when they breathe. The list contains nearly 900 substances, many of which you will recognize, that are used safely every day, such as caffeine.

The agency that administers the law, the Office of Environmental Health Hazard Assessment (OEHHA), has made clear that Proposition 65 primarily is about providing notification to consumers that a listed substance is present in a product or facility. It has been referred to as a “right to know” law. Proposition 65 does not regulate product safety. Merely because a product contains a listed substance does not mean that a product is in violation of any product safety standards or requirements. In fact, a product can contain a listed substance that has been specifically approved as safe for use in the product by an expert federal or state regulatory agency.

The law also requires anyone doing business in California to provide a “clear and reasonable” notice before exposing anyone to a listed substance at a level above the “safe harbor” level for that substance if one has been established (see below). By statute, the notice is called a “warning” even if no human health risk is presented.

Q: Why did OEHHA propose adding styrene to the list?

A: The Notice of Intent to list starts a comment and review process for styrene. It may take months or longer for the process to be completed. The agency actually may decide that styrene does not meet the statutory criteria for listing, in which case the listing will not occur. OEHHA also can decide to list styrene after the comment period has closed.

OEHHA has listed styrene under the “Authoritative Bodies” mechanism, one of several listing mechanisms. Under this mechanism, California adds a substance to the list if a designated expert body has made a determination about the substance that satisfies Proposition 65 criteria. In this case, the authoritative body is the U.S. National Toxicology Program (NTP), which identified styrene as “reasonably anticipated to be a human carcinogen” in its 12th Report on Carcinogens in 2011.

Styrene has undergone decades of scientific review, and it is not categorized as a known human carcinogen by any regulatory or scientific review agency anywhere in the world.

Q: Does OEHHA’s listing do anything to change FDA’s approval of polystyrene for use in food contact applications?

A: No. FDA has approved polystyrene as safe for use in contact with food, and specifically considers the tiny amounts of styrene that migrate into food as part of its calculation. In light of the 2011 NTP actions, FDA scientists once again reviewed the safety of polystyrene and published an update in 2014 that reconfirmed the safety of polystyrene for use in contact with food. The update indicated styrene monomer concentrations in various types of polystyrene food contact materials tested (including utensils, bowls, cups, cup lids and take-out containers) were below US FDA safety limits.

Q: What is a “safe harbor” level for a substance?

A: For substances on the list related to carcinogenicity, the safe harbor level is the “no significant risk level” (NSRL). An NSRL is defined as the level of exposure that would result in not more than one excess case of cancer in 100,000 individuals exposed to the substance over a 70-year lifetime. In other words, a person exposed to the substance at the “no significant risk level” for 70 years would not have more than a one in 100,000 chance of developing cancer as a result of that exposure. A business has a “safe harbor” from Prop 65 warning requirements if exposure to a substance occurs at or below the NSRL. To date OEHHA has established safe harbor levels for 300 listed chemicals.

Q: Did OEHHA establish an NSRL?

A: OEHHA proposed an NSRL of 27 micrograms per day for styrene – the agency will accept comments on this proposal until June 6

Q: Is there a possibility that polystyrene foodservice packaging may need to be labeled with a Prop 65 notice?

A: If exposure to styrene is below the NSRL, no label would be required. Because FDA regulates polystyrene used for foodservice, we already have very good data on styrene migration and exposure. PFPG is developing guidance to help polystyrene foodservice manufacturers make the exposure calculations needed to support company decisions about labeling.

Q: When would “anyone doing business in California” need to determine whether a label is needed?

A: Manufacturers and others have one year from the time a substance is actually listed to determine whether or not a label is needed and to have products and facilities labeled.

Q: Are there resources available to help me determine whether a label is needed?

A: PFPG is developing guidance to help polystyrene foodservice manufacturers make the exposure calculations needed to support company decisions about labeling.

Q: Would use of polystyrene foodservice packaging be restricted in California – or elsewhere – by a Prop 65 listing of styrene?

A: No. As stated by OEHHA, Prop 65 “does not ban or restrict the use” of any given substance or product. Presence of a substance on the Prop 65 list does not affect regulatory status with FDA, other federal or state agencies, or other international regulators.

Q: What have regulatory agencies and public health organizations said about the safety of polystyrene foodservice packaging?

A: Many agencies and organizations have determined that polystyrene foodservice packaging is safe for use.

    • U.S. Food and Drug Administration: In the U.S., FDA strictly regulates all food packaging materials, including polystyrene. FDA has determined for more than 50 years that polystyrene is safe for use in contact with food.
    • U.S. National Toxicology Program: NTP Director Dr. Linda Birnbaum, Ph.D., was quoted widely in Associated Press reports in June 2011: “Let me put your mind at ease right away about polystyrene foam* …[the levels of styrene from polystyrene containers] are hundreds if not thousands of times lower than have occurred in the occupational setting… In finished products, certainly styrene is not an issue.” John Bucher, NTP Associate Director, was quoted in Associated Press reports in August 2011: “The risks, in my estimation, from polystyrene are not very great,” he said. “It’s not worth being concerned about.”
    • U.S. National Institutes of Environmental Health Sciences (NIEHS): NIEHS in June 2011 noted: “Styrene should not be confused with polystyrene (foam)*. Although styrene, a liquid, is used to make polystyrene, which is a solid plastic, we do not believe that people are at risk from using polystyrene products.”
    • American Cancer SocietyBloomberg News in June 2011 reported that American Cancer Society Chief Medical Officer Otis Brawley said, “Consumers don’t need to worry about polystyrene cups and food containers…” Quote: “I see no problems with polystyrene foam* cups.”

For More Information:

Original quotes used the term “Styrofoam”. STYROFOAM™ is a registered trademark of The Dow Chemical Company that represents its branded building material products, including rigid foam and structural insulated sheathing and more. The brand name often is misused as a generic term for polystyrene foam foodservice packaging.


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