Much has been written about hazardous materials decontamination over the years as far as who does it, where it is done, how it is done, why it is done, and when it is done. But, there is very little information or guidance pertaining to how to assure decontamination (decon) efforts are adequate. For the most part, when responders and/or victims complete their travel through the decon corridor an assumption is made that they are clean. But, is this value judgment safe? Can responders unequivocally and without reservation say that each and every person who has been deconned is clean? If you cannot answer "yes" to this question then you (your agency) have some work to do.
You may counter the question above by stating that your decon efforts of the past have been successful in that no post decon exposures or illnesses have occurred. Maybe, your track record shows an over-reliance on chance or even luck. OSHA, the federal agency who watches over hazmat response, realizes the importance of conducting decon efforts and assuring its effectiveness. Over the last 15 years several OSHA plan states have issued citations and fines to fire departments for lack of decon efforts, including assuring decon effectiveness. All of the citations are based on the Hazwoper law found in 29 CFR 1910.120 (q). Based on these legal requirements and personnel safety issues there is more than enough motivation to take the steps that assure effective decon efforts are employed, but how?
The old reliance on guesswork will simply not be defensible if cited by an OSHA representative or even if called to testify in court because of a lawsuit. A more defensible approach would be to develop documented methods of assuring decon effectiveness. Essentially, there are only two methods that can be utilized to determine if decon efforts are effective: qualitative and quantitative.
Qualitative methods to determine decon effectiveness involve making judgment decisions on whether all harmful contaminants have been removed from responders and victims and their clothing. This usually involves a visual inspection. Some agencies have applied colored syrup to responder's clothing before they undergo decon. This way the decon personnel can judge their efforts during the decon process by working to remove the syrup. Again, if no syrup can be seen after responders exit the decon corridor then the assumption is made that the responder is clean because any real contaminant was probably washed off along with the syrup.
Another visual method involves the employment of a fluorescent dye which is again applied to responder's clothing before the decon process. While most of the dye can be seen during the decon process and therefore removed, any dye that remains can be detected under an ultraviolet light. If contamination is left on a responder a UV lamp that shows bright yellow or greenish residue will alert decon workers that more decon efforts are needed. These dyes can be prepared by adding sodium fluoroscein salts to water or even by purchasing commercially prepared solutions. Still, the qualitative methods leave too much safety to guesswork. Just because all of the syrup or most of the fluorescent dye has been removed does this mean the actual hazardous material has been removed? Also, if some of the dye is detected under UV light how much residue is considered safe? Finally, would we really apply syrup or dye to victims in street clothes, especially if they are in need of medical attention? Merely asking these important questions make qualitative methods seem too subjective.
Quantitative methods that employ environmental sampling techniques can detect liquid and gas contaminants in small, numeric amounts to determine decon effectiveness. The instruments that would be needed would consist of a mix of expensive and elaborate and inexpensive and simple instruments. Employment of this technology would enable decon personnel to detect and measure contaminants and then decide a course of action. In the area of decontamination this would almost always neccessitate more decon efforts.