Upholding science in health, safety and environmental risk assessments and regulations.

A public appeal has been advanced by a large group of scientists, concerned that science has been misused in attempting to quantify and regulate unmeasurable hazards and risks.1 The appeal recalls that science is unable to evaluate hazards that cannot be measured, and that science in such cases should not be invoked to justify risk assessments in health, safety and environmental regulations. The appeal also notes that most national and international statutes delineating the discretion of regulators are ambiguous about what rules of evidence ought to apply. Those statutes should be revised to ensure that the evidence for regulatory action is grounded on the standards of the scientific method, whenever feasible. When independent scientific evidence is not possible, policies and regulations should be informed by publicly debated trade-offs between socially desirable uses and social perceptions of affordable precaution. This article explores the premises, implications and actions supporting the appeal and its objectives.

Toxicology and epidemiology: improving the science with a framework for combining toxicological and epidemiological evidence to establish causal inference.

Historically, toxicology has played a significant role in verifying conclusions drawn on the basis of epidemiological findings. Agents that were suggested to have a role in human diseases have been tested in animals to firmly establish a causative link. Bacterial pathogens are perhaps the oldest examples, and tobacco smoke and lung cancer and asbestos and mesothelioma provide two more recent examples. With the advent of toxicity testing guidelines and protocols, toxicology took on a role that was intended to anticipate or predict potential adverse effects in humans, and epidemiology, in many cases, served a role in verifying or negating these toxicological predictions. The coupled role of epidemiology and toxicology in discerning human health effects by environmental agents is obvious, but there is currently no systematic and transparent way to bring the data and analysis of the two disciplines together in a way that provides a unified view on an adverse causal relationship between an agent and a disease. In working to advance the interaction between the fields of toxicology and epidemiology, we propose here a five-step "Epid-Tox" process that would focus on: (1) collection of all relevant studies, (2) assessment of their quality, (3) evaluation of the weight of evidence, (4) assignment of a scalable conclusion, and (5) placement on a causal relationship grid. The causal relationship grid provides a clear view of how epidemiological and toxicological data intersect, permits straightforward conclusions with regard to a causal relationship between agent and effect, and can show how additional data can influence conclusions of causality.