Synergist - June/July 2010

guide based on answers to the following questions: • Is there an evacuation?

• Is product on the ground?

• Is there a fire?

• Are there reports of injuries?

• Is the area populated?

• Are sensitive receptors (e.g., hospitals, day cares, nursing homes, schools) nearby?

• Are there impacts to water supplies?

• Does the facility have a history of releases?

• Does the release have a high potential to disrupt commerce?

information must originate from a credible source and be expressed in lay terms.

Environmental Chemical Releases Proper monitoring must be implemented quickly in all affected environmental media, adjusted to meet changing conditions, and performed constantly for the duration of the release, both to protect workers and offsite receptors and to generate complete documentation of the incident. Responses to airborne releases should include 360-degree perimeter and community monitoring at locations of interest (e.g., exclusion zone perimeters, schools, nursing homes, residential areas) and at the breathing zone to represent human exposures.

If the facility does not have monitoring resources, skilled third-party environmental monitoring teams are necessary. Extensive knowledge of monitoring and sampling methodology, the capabilities and limitations of monitoring equipment, and the proper documentation of equipment maintenance and calibration are essential to collect sound data. Air dispersion modeling may also help predict the extent of chemical plume movement and the resulting concentrations.

Special to the Digital Edition

The digital edition of this issue includes a special section, unavailable in print, on pre- and post-emergency response. Look for the digital edition to reach your inbox in late July.

the best first response. However, PPE may have its own hazards and limitations (e.g., restricted motion, limited line of sight, and physiological stresses), so quick data collection is necessary to place workers in the most appropriate PPE.

In our experience, if the answer to some or all of these questions is “yes,” the public will view the incident as significant—even if the chemical has relatively benign toxicological properties.

Human Health Hazards

Because of the urgent need for health hazard information, industrial hygienists must have access to useful information about chemicals’ effects on human and environmental health. Toxicology support personnel should be intimately involved with identifying the chemicals, summarizing toxicological data (e.g., dose-response data, epidemiological studies), and determining the routes of exposure that pose the greatest risk to workers and the community. This information is also necessary for proper hazard communication, and not only with onsite responders. Local medical facilities need to be briefed on decontamination issues (e.g., do exposed persons pose a secondary contamination risk to health-care workers?) and chemical hazards.

MSDS are often used to communicate health hazard information to treating physicians, the public, and first responders. We do not agree with this practice. While we use MSDS to identify the product and percent composition of chemicals and physical chemical properties, we rely on more appropriate sources of health hazard information for dissemination to the public or emergency room physicians, including the Agency for Toxic Substances and Disease Registry (ATSDR) Medical Management Guidelines, the documentation of TLVs®, AIHA® ERPGs, and Acute Exposure Guidelines levels (AEGLs). The scientific

Exposure Guidelines and Action Levels Responders must also identify protective action levels. For example, responders might enact an action level that is one-half of the appropriate occupational exposure limit (OEL) so that changing conditions identified through environmental monitoring can lead to appropriate actions before the OEL is exceeded. Hazard mitigation activities can cause rapid changes in chemical concentrations in work areas, which could require an upgrade of worker protection. Responders must also develop community action levels to help determine the extent of evacuation areas.

Personal Protective Equipment (PPE) Responders must identify the proper PPE for workers involved in hazard mitigation and cleanup. Frequent re-evaluation of environmental conditions is necessary to make informed decisions about upgrading or downgrading PPE. When environmental conditions are unknown, or when initial monitoring data is still being acquired, the most protective PPE is often

Operational Approaches to Hazard
Mitigation

Responders must be able to identify proper responses to chemical releases as they occur and if there is reasonable anticipation of explosion, fire, or failure of chemical containment mechanisms. Also important is the placement of proper chemical containment and decontamination equipment for limiting contamination to the exclusion zone.

As conditions change and/or mitigation progresses, the approach to hazard mitigation must change accordingly. For example, dealing with a chemical fire poses new challenges. Should responders fight the fire, or allow it to burn? Fire hazards, including smoke and vapor exposures, change when the fire is controlled; in post-fire cleanup operations, workers face structural hazards and the potential for dermal exposure to surface contamination. Response leaders must be able to adjust plans quickly and appropriately to respond to the change in conditions.

Another consideration is the accumulation of hazardous waste from mitigation activities. Facilities must be prepared to identify hazardous waste, quickly handle waste collection and storage prior to removal and disposal, and ensure that workers involved in cleanup are properly certified and trained for hazardous waste work.

Glenn C. Millner, PhD, is founding partner and principal toxicologist with the Center for Toxicology and EnvironmentalHealth,LLC(CTEH®)inNorthLittle Rock,Ark.Hecanbereachedat(501)801-8500or gmillner@cteh.com.