Many industrial sites have chemical detection and release surveillance systems that act as a first line of defense mitigate the potential for minor issues to develop into large-scale chemical incidents. Through the efforts OSHA and the National Institute for Occupational Safety and Health (NIOSH), worker health surveillance programs, including those for workers with the potential for chemical exposures in the workplace, have been put into place. These programs involve the use of environmental sensors within the workplace and/or biomonitoring programs to track chemical exposures in workers. Understanding the capabilities of these chemical release recognition systems and how the information they provide can be used to inform a response outside the facility perimeter is important for local chemical incident response planning.
Personal, handheld, and large area sensors may all be used in the workplace to monitor chemical levels in the work environment and chemical exposures in workers. Personal sensors are small, lightweight units that are attached to workers while they perform their duties. Although available real-time personal sensors are easy to use, they provide less and lower quality data than sampling devices for laboratory analysis. In general, they also provide coverage for fewer chemicals. Most personal real-time sensors are able to quantify between one and four chemicals, although a handful can measure up to ten or more.
Common chemicals detectable by these sensors include:
- Ammonia
- Carbon monoxide
- Chlorine
- Hydrogen cyanide
- Hydrogen sulfide
- Nitrogen dioxide
- Phosphine
- Sulfur dioxide
Handheld and large area detectors have the advantage of being able to measure the levels of tens or hundreds of chemicals; these could be real-time or laboratory sensors.
Data collected by chemical detector technologies in the workplace can be complemented by biomonitoring programs. Biomonitoring refers to a variety of methods that assess human exposure to chemicals by detection and quantification of the chemicals’ biomarkers in different biological sample matrixes. These biomarkers can be the chemicals themselves, their metabolites, or the products of an interaction between the chemical and a target molecule in the body. Generally, biomonitoring in humans is accomplished using a variety of analytical methods like chromatography, mass spectrometry, and spectroscopy on urine, blood, or hair samples. Since these programs generally require off-site laboratory analysis, they are likely to be of little help in detecting acute chemical release incidents, although their ability to identify chemicals by type may be useful in determining the appropriate treatment for acute injuries, and in recognizing chronic worker exposures due to long-term chemical leaks. As with other testing programs, biomonitoring will only identify exposures to a usually limited list of chemicals; due to metabolic processes, the detection window post-exposure also may be limited.