Regulating groups of chemicals: a cost-effective option for chemical safety

By Bob Diderich and Shanda Moorghen, OECD Environment Directorate

There are currently more than 23,000 chemicals produced or imported at quantities of more than one tonne per year just in Europe. We can find them in the clothes we wear, the shampoos we use, and in many other of our daily activities.

This number alone is indicative of the regulatory scope needed if this is dealt with by adopting a substance-by-substance approach in order to evaluate the safety of each chemical. Policy makers are now looking at grouping the substances as a potential solution to facilitate decision-making on chemical safety. But challenges persist.

The benefits of chemicals use must be balanced with effective regulation

Chemicals often represent an essential component in various economic sectors. We can appreciate their importance in the textile industry, whether it is in the form of pesticides to grow raw materials such as flax or in fabric dyeing for apparel. However, the benefits gained can come with significant risks . The health and environmental consequences of ineffective chemical safety regulations can be disastrous. For example, failures to regulate persistent organic pollutants (POPs) could make people exposed to the chemicals more likely to be diagnosed with cancer or to suffer from reduced cognitive functions. Some POPs made headlines in the 1960s when author Rachel Carson published a seminal book on the environmental impact of DDT, a chemical compound found in insecticides that were widely used in agriculture at the time.

While it is crucial for their safe use, the risk assessment of thousands of chemicals can be a costly and difficult process. The ground-breaking Stockholm Convention on Persistent Organic Pollutants was a first step towards easing the regulatory procedure by addressing all chemicals that share similar intrinsic properties (i.e. chemicals that are Persistent, Bio-accumulative and Toxic or PBT). The Convention thereby introduced a global ban on DDT for agricultural use several decades after Carson’s book was published as part of a first group of 12 substances and is regularly adding to its list of restricted substances. The PBT-criteria for identifying Persistent Organic Pollutants were also implemented in national and regional legislations, such as the EU REACH regulation or the US Toxic Substances Control Act.

The OECD hosted a session on the topic of  grouping chemicals for regulatory decision-making during its Global Forum on Environment last month (November 2020) to discuss progress on the issue around the world, ranging from Canada to New Zealand. The panellists brought up the need for regulatory consistency between policy makers and the necessity to move away from the risks of “regrettable substitution” in a substance-by-substance approach.

“Regrettable substitution” is the process of replacing a regulated chemical with an unregulated chemical sharing the same properties. The most prominent example involves Bisphenol A (BPA). It is common to see products, such as baby bottles or cash register receipts, advertise being free of BPA, which has a significant negative impact on human health. Once BPA was dealt with by regulators, several other bisphenol variants found their way to the market and into products. Policy makers are now pursuing a grouping approach to regulate bisphenol alternatives and derivates.

The PFAS case study

Almost two decades after the Stockholm Convention was signed, the chemicals grouping approach has been mainstreamed, with the OECD focusing its work on per- and poly-fluorinated substances (PFAS). These chemicals can be found in a number of places ranging from the textile industry to fire-fighting foam. Like many chemicals, they come with their own array of environmental and health concerns. Many PFAS are persistent substances, which means that they don’t break down in the environment, and many can also bioaccumulate. This can be detrimental to wildlife by introducing toxic components to the food chain. Some PFAS have been found to pose a significant risk to human health, with issues linked to the reproductive system and cognitive functions. However, the issue of “regrettable substitution” has also plagued progress on regulatory measures on PFAS. For example, bans on long-chain PFAS triggered the emergence of several forms of short-chain PFAS.

Over the last year, the EU has adopted the grouping approach for the first time with PFAS, under a proposal by the EU Commission to limit all substances falling into that category under the Drinking Water Directive. While legislators were unable to agree on addressing all PFAS, they are monitoring a provisional list of 20 substances until the EU Commission guarantees a method for measuring all PFAS, a process that is expected to be completed in the next three years.  This regulatory approach to PFAS has also allowed for alternatives to emerge rather than industry converging to a simple substitution with substances of similar intrinsic characteristics. A recent OECD report highlighted non-fluorinated alternatives to short-chain PFAS, even though issues persist over the inevitable cost differential.

New Zealand approach vs EU approach

The necessity of group standards does not ensure consensus between countries, nor does it ensure a harmonised approach. This divergence can be observed, for example, between New Zealand and the EU. In New Zealand, chemicals grouping falls under the Hazardous Substances and New Organisms (HSNO) Act. The legislation includes more than 200 group standards and aims to facilitate the process of chemical safety in key areas. The regulation does so by allowing industry to self-assign a substance to one of the group standards rather than going through the country’s Environmental Protection Authority (EPA), but records should be available for public inspection.

The methodology is different for the EU’s Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation. In this case, the burden of proof is on companies to guarantee the risk management of the chemical substances they use. If they fail to do so, the substance may be considered unsafe, which can lead to a ban. The EU has also defined the criteria for very persistent and very bio-accumulative (vPvB) substances. The EU has adopted this approach to regulate other groups of chemicals, which can be observed with the automatic ban of carcinogenic, mutagenic and reprotoxic (CMR) substances in consumer products.

However, the EU’s recently adopted chemical safety strategy, a key component of the EU  Green Deal, seeks to expand chemicals grouping. The European Commission indicates a preference for increasing the scope of group standards by proposing groupings for other chemicals like persistent, mobile and toxic substances, while gradually moving away altogether from the substance-by-substance approach. It also deals specifically with the issue of PFAS, with the European Commission moving towards a group approach and banning all non-essential use.

The costs of a substance-by-substance approach can be prohibitive for many countries and the prevalence of “regrettable substitution” inexorably complicate the regulatory process. However, with the potential health and environmental consequences, the importance of chemical safety cannot be underestimated. Group approaches to facilitate risk management can be a vital tool to ensure chemical safety.

Further reading:

OECD (2020), Chemical Safety and Biosafety Progress Report, OECD Publishing, Paris.

OECD (2020), PFASs and Alternatives in Food Packaging (Paper and Paperboard) Report on the Commercial Availability and Current Uses, OECD Publishing, Paris.

OECD (2018), Considerations for Assessing the Risks of Combined Exposure to Multiple Chemicals, OECD Publishing, Paris.

Find out more about OECD work on chemical safety: www.oecd.org/chemicalsafety/