Emerging Issues in Risk Assessment


The Risk Assessment Committee has evaluated the impact of a number of critical issues during the last decade. These have included: 

1. Availability of accurate, dependable toxicology information upon which to base a risk assessment.

Little or no toxicology information, or limited types of information, exists for a number of chemical agents (e.g., antineoplastic agents and other pharmaceutical agents) 

There are reports with conflicting toxicological end results for the same agents (e.g., adverse vs. beneficial effects of ozone at concentrations at or below 0.1 ppm), and most studies (or reports from toxicity studies) other than pharmaceutical studies ignore findings which indicate beneficial responses. 

There frequently are significant differences in the toxicological results found in animal studies vs. toxicological impact to humans (e.g., for butadiene there are different cancer risks to the mouse vs. to the rat vs. to humans), yet the mouse information is still commonly used to establish human exposure limits.

2. Availability of accurate, dependable exposure assessments upon which to base a risk assessment.

There is a need to develop the science of exposure assessment such that we will have the necessary tools to objectively evaluate (or a least reasonably screen) the majority of exposure scenarios in the work place and the non-occupational settings. 

Exposure assessment strategies, data, methods, and models have been developed, and there has been some standardization of approaches, but not on a broad scale. Information on chemical uses, environmental releases, activity patterns, methods for assessing dermal exposure, and development and validation of acceptable predictive approaches are key areas for additional work.

3. Determining which model to use for assessing risk, and using it appropriately.

Several models have been developed for conducting comprehensive risk assessments. However, the more complex models have not been able to be validated, and information to-date appears to indicate the simple models to be as defendable as the complex models. 

Risk assessment models must be carefully selected and appropriately used. Even if the appropriate model is selected, use of the most adverse findings (usually from animal studies) may produce unreliable results. As an example, an old EPA risk assessment used for evaluating worker risks in the rubber industry predicted that 100% of the workers in the industry between 1940s and 1950s would have died of cancer, which is very incorrect. 

Attempt to relate risk assessment results from a model with existing epidemiology information when available, or recommend that epidemiology information be collected if the risk assessment indicates concern.

4. Communication of relative risk.

It is difficult for individuals in the general public to make informed decisions regarding minimization of their personal risk if they are uninformed or misinformed. The general public may make uninformed or misinformed decisions due to use (or misuse) of statistics, of the risks associated with materials they encounter, and/or due to actions they may participate in or take. For example, the risk to a person doing laundry and using household bleach, required by law to contain a minimum of 5.25% (52,500 ppm) sodium hypochlorite vs. the risk of using the same material in a workplace setting. All too frequently because of the way training is done (focusing on the workplace only) and the emphasis in the media on how hazardous the work environment is, the worker perceives (and may believe) the material is only hazardous in the workplace setting. Individuals should have training that provides them with relevant, comprehensive risk information both at and away from the worksite. They should be educated to have equal respect for potentially hazardous agents/actions where ever they encounter them. 

Lack of information or use of misinformation may result in unnecessarily stringent standards or loss of product. For example, the U.S. and Canada both evaluated saccharin, with the U.S. study finding no adverse effects, but the Canadian study did. However, the end of the study report from Canada indicated there may have been a mix-up of the rats in the study, and that the study should be repeated. The last part was not communicated to the legislators and saccharin almost became unavailable (as happened with cyclamate), but a compromise was reached to put a warning on all saccharin products and allow it to stay on the market.

5. Attempt to better associate exposure information to various agents with actual dose and dose-response information.

Much additional work is needed on the evaluation of exposure(s) to an agent and relating that qualitative information to actual dose and effects to the body or specific organs.

It is the view of the committee that the next decade will include continuing work on toxicology, exposure assessment, and risk assessment and risk communication. Indeed, the need for this work will become much more acute in the next few years as the High Production Volume (HPV) Challenge Program is implemented and screening level toxicity and hazard data becomes publicly available in the next 5 years for approximately 3,000 chemicals. These emerging issues will include: 

Improving toxicological information regarding the relevance of animal results to humans.  Improved interpretation of animal study results based on pharmacokinetic differences and similarities to better determine relevance of exposures to humans. 

Improving the science of exposure assessment so that we will have the necessary tools to objectively evaluate (or at least reasonably screen) the majority of exposure scenarios in the workplace and the non-occupational settings. If we do not address this need, it will remain the most pressing issue in risk assessment; indeed it will get much more acute as toxicity and hazard data come in on almost 3000 compounds in the next 5 years via the HPV Challenge program. 

Improving education of all individuals, scientists, regulators, and general public on relative risk. Providing information in a usable (more understandable) manner, and in a fashion able to be used for prioritizing risks, and making informed decisions at all levels. 

Improving communication of relative risk. Professional organizations like AIHA, ACGIH, SOT, etc., need to enhance their activities related to informing both members and the community at-large of the relative risk of commonly used chemicals, and of common activities. 

Improving scientific methods to associate exposure information, especially inhalation and/or ingestion of air contaminants and skin contact with surface contamination, to various agents with actual dose and dose-response information. Additional in-vitro and in-vivo toxicology studies are necessary, including use of human tissue in some studies, and use of human (epidemiology) studies to determine dose-response information and provide better data for conducting risk assessments.

These emerging issues may open up substantial opportunities for the industrial/occupational hygiene profession. These individuals are uniquely qualified to evaluate potential hazards, exposures, and risks to chemicals, and to take appropriate actions where needed to effectively and efficiently manage and communicate these potential risks to workers, the general public, consumers, and communities. In order to achieve these goals, industrial/occupational hygiene professionals will need to expand their scientific and technical knowledge and capabilities, and collaborate with allied professionals such as toxicologists, public health officials, communication and educational professionals, etc.