The European Chemical Agency has looked at a group of phthalates as a combination when considering risks associated with exposure

The European Chemical Agency (ECHA) has for the first time looked at a group of chemicals as a combination when considering risks associated with exposure – rather than looking at each chemical in isolation.

Scientists like to look at things in isolation. It is a central tenet of the business: fix all the variables bar one so that you can home in more quickly on the root cause of any changes in outcome.

But the real world isn’t very obliging in this regard. Consumer products invariably contain more than one chemical that can sometimes interact with biological systems in a cumulative manner presenting a difficult situation for regulators tasked with determining risks associated with exposure. In May, the European Environment Agency highlighted the dangers of the so-called cocktail effect, advocating a precautionary approach.

The ECHA was asked by Danish authorities to assess four phthalates – bis(2-ethylhexyl)phthalate (DEHP), dibutyl phthalate (DBP), benzylbutylphthalate (BBP) and diisobutyl phthalate (DIBP) – used as plasticisers in the production of a wide range of consumer goods but a source of concern for many years owing to their ability to disrupt male hormones.

The four phthalates – as isolated chemicals – are already covered by Reach (registration, evaluation, authorisation and restriction of chemicals) regulations designed to reduce use in the long term. But the Danish authorities argued that additional regulation, in the form of a combined exposure limit, was needed because they affect biological systems in the same way.

The committee for risk assessment concluded that the proposed restriction was not justified, noting a steady decline in use over the last decade, a trend expected to continue. The draft opinion has been submitted for public consultation for 60 days, with adoption of the final opinion planned for December 2012 at the latest.