Improving the Scientific Basis of Risk Assessment Through Harmonization

April 1, 1997

Office of Environmental Health Hazard Assessment former Director Richard A. Becker, Ph.D., released this statement to clarify ongoing work at OEHHA to foster consistency and harmonization of risk assessment activities across all Cal/EPA organizations and with like programs within the United States Environmental Protection Agency. Recognizing the importance of findings and recommendations of the Risk Assessment Advisory Committee, Governor Wilson issued Executive Order W-137-96 designating the Office of Environmental Health Hazard Assessment (OEHHA) as the lead State agency in this effort.

Harmonization of State and Federal risk assessment activities should be viewed as a two-way exchange of scientific analysis, methods and approaches.

Conceptually, harmonization should not be equated as simply standardization. Instead, harmonization of risk assessment activities should be viewed as:

• Understanding the methods and practices used by various like scientific organizations;

• Developing a willingness to work toward greater interaction and cooperation in evaluations of health hazards and risk assessment methods, particularly in the areas of incorporating new scientific knowledge and models;

• Consideration of alternative, plausible scientifically sound approaches to enhance thoroughness and increase scientific credibility, and

• Making the most effective use of our limited resources by information sharing.

For example, the recent development of stochastic risk assessment guidelines by OEHHA represents new scientific approaches where California has clearly established its leadership in this field, and is in a position to share this important work with sister agencies within the State and federal government.

Similarly, the U.S. Environmental Protection Agency has recently developed new guidelines for assessing the cancer risk posed by chemicals, and OEHHA has initiated a pilot project putting these new cancer guidelines into practice for a few select chemicals to evaluate the strengths and limitations of the guidelines.

Harmonization of risk assessment work was one important theme of the Risk Assessment Advisory Committee, an external advisory Committee who reviewed the risk assessment practices of Cal/EPA. As with all new concepts, the evolution of thought in this area has been accompanied by a certain amount of skepticism. As risk assessment methodologies mature, and risk assessment is increasingly integrated across all environmental media and used as the foundation for health and environmental protection measures, it has become increasingly apparent that different organizations using divergent risk assessment methodologies for the same chemical or comparable situations creates a difficult situation for risk managers, policy makers and stakeholders alike.

The Risk Assessment Advisory Committee noted that there are "cases California differs significantly from the average for the U.S. such as in diet, weather, lifestyle and population demographics, so that differing risk characterizations may be legitimately derived for California versus the whole U.S. The Committee also found that some differences in risk assessments prepared by Cal/EPA and U.S. EPA are difficult to explain."

As stated in the report (ref. 1) "The Committee notes with favor the beginning efforts made by Cal/EPA personnel in harmonizing their risk assessment activities with their federal counterparts." The Committee's number-one recommendation is that "Cal/EPA should take the lead in initiating steps to assure consistency and cooperation with U.S. EPA and other federal counterparts. Consistency in policies, guidelines, technical data, techniques, and work products should be the goal to the extent possible and consistent with applicable federal and state laws and policies. Sharing of workload and model development efforts are examples of such cooperation. Working together on prioritization of chemical waste sites requiring risk assessment is another. Setting up a regular forum for resolving differences is a third."

Harmonization of risk assessment policies, practices and procedures both within Cal/EPA and with the Federal government health and environmental agencies will promote greater consistency, allow for more effective use of our limited resources, and lead to more effective environmental and health protection decisions.

Conceptually, harmonization should not be interpreted as moving to the lowest common denominator, nor stifling the advancement of new scientific approaches just for the sake of consistency. Instead, it is an opportunity for us to lead in the implementation of up-to-date, science-based risk assessment approaches and risk assessment policies. The challenge we face is to achieve consistency, while at the same time providing flexibility to address California-specific issues or situations, which considers all pathways and routes of exposure.

Harmonization will focus our efforts on moving beyond single medium (e.g., air, water) approaches into a more unified, holistic, multi-media methodology to evaluate threats posed by environmental chemicals. It will also focus our resources on the evaluation of existing differences that have substantive impacts, while at the same time eliminating differences for cases where there is no compelling scientific justification to be different.

Reference 1.
Risk Assessment Advisory Committee (1996) A Review of the California Environmental Protection Agency's Risk Assessment Practices, Policies, and Guidelines. Published by the Office of Environmental Health Hazard Assessment, California Environmental Protection Agency.

Last Updated April 22, 1997