A team from the Institute for the Environment at Brunel University has found that commonly applied “uncertainty factors” led to “ill-founded” assurances about the effects of chemical mixtures. The review, published in the journal Environmental Health, found no support for the “urban myth” that the default uncertainty factor is over-conservative.

OV Martin and others. Dispelling urban myths about default uncertainty factors in chemical risk assessment – sufficient protection against mixture effects?, Environmental Health, volume 12, number 53, 2013. Chemical Watch (subscription only). Risks 614.