Introduction

There are three different needs for risk assessments. One is for developers and manufacturers of new chemicals and products. They need risk assessments to help guide decisions about occupational exposures, labeling, and product liability, and have the luxury of dealing with one or, at most, a few chemicals at a time. A second need is related to regulatory requirements. Legislation may mandate that either manufacturers and/or regulatory agencies conduct risk assessments, and may also require that they be reviewed by governmental personnel and/or advisory bodies. A third need is for research planning. The risk assessment framework can be used to identify critical gaps in knowledge as well as summarize available knowledge, and a compilation of critical knowledge gaps can provide valuable input into the research planning process. There are many and varied issues that need to be addressed in quantitating risks. They provide some valuable inputs for a topic of increasing importance in environmental protection.