It is not easy to evaluate risks. We are all exposed, directly and indirectly, to an array of chemicals, medicines and other products, many of which have only recently been developed or synthesized. Absolute safety can rarely be assured. Short-term effects can be assessed and observed, but long-term reactions are difficult to foresee, though they can be disastrous both to people and the wider environment. TUNZA asked David Gee of the European Environment Agency – who has put together two major studies of man-made hazards entitled Late Lessons from Early Warnings – to guide us through the maze.
Q Are the effects and risks of man-made hazards – like chemicals, asbestos or lead in petrol – similar to those of natural hazards?
A There are some similarities, such as the need for preparedness, fair and prompt rehabilitation and compensation; and the necessity for reliable early warnings and the right balance between false alarms and prudent precaution. There are also differences: man-made hazards often cause long-term harm that creeps up silently to destroy the ozone layer, for example, or to cause devastating cancers. We can, of course, do much more to control and diminish the hazard we ourselves create, for example by using biomass-based chemicals rather than oil-based ones, and avoiding molecules that are very long-lived and persistent in the environment or that accumulate in bodies.
Q Are only humans affected or does harm also spread into the wider environment?
A Many of the hazards described in the Late Lessons from Early Warnings books mainly damaged the environment. These included chlorofluorocarbons (CFCs) used in products from fridges to aerosols; polychlorinated biphenyls (PCBs) found, for example, in components of fluorescent light fittings and PVC; emissions of ammonium, carbon, nitrogen and sulphur which led to acid rain; endocrine disrupting chemicals in weed-killers amongst other things; and tributyltin (TBT) which was used in anti-fouling paint for boats and as a wood preservative. Most of these, however, also harm people.
Q How much evidence do we need to take action to avoid harm?
A The table shows the range of different strengths of evidence that can be chosen to justify taking action, from the high ‘beyond all reasonable doubt’ of the criminal courts and scientific ‘causation’ to the relatively slight evidence that could be used to ban a pill tentatively associated with birth defects in an experiment on rats. Choosing which strength of evidence to rely on is an ethical issue, a case of deciding which consequences you are happy to live with if you prove to be wrong.
Q Some risks are inevitable, so is this a matter of deciding what risks are acceptable, given the likely benefits?
A Yes, and this too is a societal not a scientific question. For example, how much evidence do you need to persuade you not to stick a mobile phone next to the head, given that you get most of the same benefits by texting and using an ear piece? There is already suggestive evidence that the handsets cause brain cancer, especially in young people. But the authorities and phone companies would like to wait for much stronger evidence – from more cancers – before acting to reduce the hazard.
Q What is the ‘precautionary principle’ pioneered in the European Union?
A The principle was designed to help decision makers choose the appropriate strength of evidence for acting when the science is uncertain, or where there is much ignorance about large-scale exposures to potential harm, as is the case for genetically modified organisms (GMOs), weak radiations, some chemicals and nano products. It justifies action if there are reasonable grounds for concern and if the consequences of not reducing exposures could be very serious.
Q But how does this equate with innovation?
A There is a trade-off between risk taking and precaution, but we have got it wrong in so many devastating cases, such as asbestos (where the first early warning came in 1897), the ozone hole and climate change, that we need to take more care. The precautionary principle helps us to strike a better balance by asking such questions as: ‘Is this product really needed?’ or ‘are there smarter ways of meeting needs?’ In Late Lessons we showed that so-called ‘cheap’ universally used substances like asbestos, PCBs and CFCs actually held up innovation for decades, partly because they kept out competition since their real costs to society and the environment were not included in their market prices.
Q With so much manufacturing now in developing countries, can the precautionary principle in Europe make a difference?
A Yes, because it can limit trade in harmful substances such as imported toys containing lead that endanger European children, or European PCBs and other chemicals that now contaminate the Arctic. To take another example, the Cartagena Protocol on Biosafety uses the precautionary principle to try to stop the export of GMOs to countries that don’t want them.Late Lessons from Early Warnings can be accessed from the European Environment Agency at www.eea.europa.eu/publications/environmental_issue_report_2001_22. A second volume is to be published in 2011.