In June 2014 the European Commission changed the classification of styrene. Per January 1, 2016 this has had implications for managing styrene exposures in Composite component manufacturing. Also, per this date there has been a change in labeling of products that contain styrene. Bert Handels explains the background and how Aliancys is supporting its customers in managing styrene emissions in their operations.



Styrene is an important solvent for composite resins”, explains Bert Handels, REACH Program Manager at Aliancys. “It is used to dilute unsaturated polyester and vinyl ester resins to the right viscosity for the desired processing technique”. At the same time it is also a reactant. During the polymerization of the resin solution the styrene is polymerized.

The result is a composite part with great mechanical properties, chemical and thermal resistance. As a consequence, resins based on styrene have found their way in many applications in Transportation, Building & Infrastructure, Marine, Industrial and Wind energy markets.



On June 6th, 2014 the European Commission published its decision to update Annex VI of the REACH Directive, listing styrene as a CMR 2 substance for Reprotoxicity (H361d Suspected of damaging the unborn child).

Because of this EC decision, there was already a legal obligation for styrene manufacturers and importers to change their Classification & Labeling before December 1st, 2014. Since January 1st, 2016 there is now also a legal obligation for manufacturers of Unsaturated Polyester and Vinyl ester resins to change the Classification & Labeling of their finished products. Likewise, this obligation applies to manufacturers of mixtures and semi-finished products if styrene content is above 3 %.



The changing classification requires manufacturers of composite components to minimize the exposure of workers, consumers and the environment to styrene”, explains Bert Handels. “Therefore such classification can have implications for handling styrene in our customers operations (which may include emission control, associated equipment investment, operating permits).”

Whenever a substance is classified as CMR 2, the Chemical Agents Directive (Directive 98/24/EC) prescribes the mandatory application of a so-called “occupational hygiene strategy” (where the starting point is “zero” exposure of humans) and processes for health surveillance to be put in place.

Such an occupational hygiene strategy includes:

  1. Reduction of use by replacement
  2. If step 1 is not possible then manufacturing and use in a closed system
  3. If step 2 is not possible then implementation of collective protection measures (i.e. local exhaust, air ventilation systems)
  4. If step 3 is not possible then implementation of individual protection measures (Personal Protective Equipment) 

Aliancys supports our customers to better understand what the application of an occupational health strategy can mean for their operations”, adds Bert Handels. “In such a way we can really help our customers right in their production, making available our expertise we have built over years.”



Aliancys believes styrene is safe to use if exposure is kept below the appropriate concentration limits. This also requires that the correct operational conditions are used and the right personal protective measures are taken. The Styrene REACH Consortium has proposed a DNEL (Derived No Effect Level) for worker inhalation exposure of 20 ppm as an 8-hour time-weighted average in their REACH dossier.

The actual Occupational Exposure Limits for styrene may not be the same as the this DNEL value, and do differ from country to country in the EU. The range is now from 10 ppm in Sweden to 100 ppm in the UK.


Aliancys has developed calculation models that can help our customers to better understand the concentration of styrene in their factory, depending on resin type and quantity used, and the applied ventilation measures”, explains Bert Handels. “This will support customers in their discussions on styrene exposures with local authorities (like Labor and Environmental Inspection).” Also this will provide them with better insight on potential investments required to reducing emissions. Customers can consult their Aliancys Technical Service responsible for more information on these calculation models.



In order to reduce styrene emissions, it is best to work right at the source. There are LSE (Low styrene emissions) resins available from Aliancys for hand lay-up and spray-up processes. In addition Aliancys has a broad range of styrene-free resins available for many important transformation processes.

Besides changing the resin, the air quality can be improved by the introduction of air ventilation and/ or air purification equipment. In many cases, this does require capital investments.



We already have customers asking for styrene-free resins because they don’t want to expose their workers to any potential health risks, or because their customers (including OEMs) simply do not want to have products with styrene.

Aliancys has a broad range of styrene-free resins commercially available. The reactive diluents used in these styrene-free Atlac® Premium, Beyone™ and Daron® resins are not CMR classified based on the actual information from the European ECHA database. Styrene-free resins will have slightly different characteristics than styrene-containing resins, simply because the chemical composition is different. Please consult you Aliancys Technical Service representative for more information.

Aliancys wants to fully understand the business of our customers”, concludes Bert Handels. “Therefore, it goes without saying that we want to help them  to run their operation smoothly and promote safe working conditions for their operators.”


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AOC Aliancys

AOC Aliancys

AOC Aliancys is the leading global supplier of polyester and vinyl ester resins, gelcoats and specialty materials used for the composites industry. With strong capabilities around the world in manufacturing and science, we deliver unrivaled quality, service and reliability for today, and are creating innovative solutions for tomorrow. Together with our customers, we are shaping the future of composites with new technology and applications. Visit our websites below to learn more about how AOC Aliancys can help your business be more successful.