- The precautionary principle is intended to apply to situations where there is considerable scientific uncertainty; it is not a substitute for evaluating potential health or environmental effects when sufficient information exists and is typically invoked when data are not available to evaluate potential health effects
- The 12 or so phthalates used in consumer and commercial products are very well studied, have extensive toxicity testing databases; many have been the subject of multiple government reviews
- Safe exposure levels established for phthalates are based on one or more uncertainty (safety) factors to ensure an appropriate margin of safety for the general population and sensitive subpopulations
- CDC biomonitoring data consistently indicate that the levels of phthalates to which the general population is exposed are well below established safe levels
Weight of Evidence
Government determinations on the safety of chemical products (or of chemicals in products) are based on an evaluation of the “weight of evidence”—consideration of all the available information on the particular product and weighing its potential significance of human exposures to the chemical. Typically this involves using information from tests on laboratory animals, evaluating whether the results are relevant to humans, and using uncertainty (safety) factors, typically 100- or 1000-fold, to ensure an acceptable level of protection. The greater the uncertainty about the potential health effects of a particular chemical, the larger the uncertainty factors used. For substances for which a great deal of information (and therefore less uncertainty) exists, like the dozen or so phthalates in commerce today, smaller uncertainty factors are required.
Recent calls for a precautionary approach to the regulation of chemicals mischaracterize the original language relating to the application of precaution adopted in the 1992 Rio Declaration on Environment and Development and reaffirmed in the 2002 Report of the World Summit on Sustainable Development (WSSD):
"In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation." (emphasis added)
In contrast groups advocating precaution in chemical regulation argue that, when an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically. This interpretation of the precautionary approach advocates for taking action in the absence of assessing the potential risks, a process that includes weighing the scientific evidence on both the hazards of, and exposure to, a chemical.
Regardless of which definition is used, the suggestion to apply a precautionary approach to the use of phthalates in consumer and commercial products is inconsistent with the large amount of data that exist on these products and the numerous government reviews that have consistently confirmed their safety in a wide variety of applications. These reviews have been enhanced in recent years by the availability of biomonitoring data of phthalate levels in blood and urine from the Centers for Disease Control and Prevention indicating that exposure of the general public to phthalates (both individually and cumulatively) are up to 1000 times below the levels determined to be safe; these safe levels are themselves up to 1000 times below levels that caused effects in lab animals. » learn more about human exposure to phthalates