Wet Decon, or Dry?


By P. Andrew Karam, PhD, CHP, Radiation Safety Professional

I spent eight years in the American Navy’s Nuclear Power Program – half of that time was spent on an attack submarine. It being the Navy, we did a lot of drills and exercises – we used to try to jockey for position during some drill sets, hoping to be the person lucky enough to be contaminated.

It seems a bit odd – but water was often in short supply on the submarine and we were never allowed to take nice long showers. Unless, that is, we were trying to decontaminate ourselves – then we could let the water flow for long, luxurious minutes. Nobody wanted to really be contaminated – but we loved to play the part.

That was in the 1980s, and while I sometimes heard about other decon methods after I got out of the Navy, I never put much credence in dry decon of any form. It seemed fairly clear that one couldn’t get much cleaner than through a good soaking shower.

So let’s fast-forward to a few years ago.

In the event of a radiological terrorist attack, New York City has a plan to set up a number of Community Reception Centers (CRC) – these will be able (in theory) to receive and survey 1000 people per hour, decontaminating them as necessary. The Fire Department of New York (FDNY) is responsible for surveying people passing through the CRCs and for decontaminating them as necessary.

So a few years ago I was accompanying some military visitors who were in town to talk about how our CRC plans might be applied to their needs and one of our stops was at the FDNY CRC training facility. By coincidence, one of the FDNY captains was demonstrating a “dry” decontamination technique that FDNY was in the process of changing to; it involved wiping the contaminated person off with what looked like adult-sized baby wipes.

Over the next quarter hour the captain convinced me that decontamination had changed and improved quite a bit since I’d been in the Navy. He “contaminated” two of the firefighters with the UV-fluorescent powder we’re all familiar with; he hosed one down with a decon shower, scrubbing him with a brush the same way I’d been taught to decon sailors so many years ago.

Then he wiped down the other firefighter using the “baby wipes.” Standing side by side the two men looked fairly similar, except that the one that had been hosed down was a bit soggier. But when the UV light was turned on…there was a huge difference, and the guy who’d been hosed down was a lot less decontaminated than the one who’d been wiped down. I have to admit I was surprised – and then the captain made the comment that “If you can decontaminate your baby during a diaper change then you can decontaminate someone coming out of the Hot Zone.” And of course he was right – I’d just never thought of it that way.

He also pointed out that wipes could be treated to help neutralize some contaminants or to enhance their effectiveness – another advantage over just drenching someone with water. All in all, he convinced me that the dry (or at least moist) decon was a better way to go than the wet decon I’d been accustomed to.

I’ve got to admit that, even though it’s clear to me that the wipes are a better way to decontaminate people, I find myself hoping the Navy doesn’t adopt them too quickly. We were limited to three minutes of “water time” in the shower and being lucky enough to be “contaminated” during a drill was our only chance to linger beneath the showerhead. I’d hate to rob today’s (and tomorrow’s) sailors of the occasional long soak to look forward to.

About the Author

Andrew Karam is a radiation safety professional with 35 years’ of experience in his profession, beginning with the eight years he spent in Naval nuclear power. During his career Dr. Karam has worked for state and local governments, for an environmental consulting firm, and at two universities. He has a PhD in Environmental Science and is board-certified in health physics.

Dr. Karam has served on two committees of the National Council on Radiation Protection and Measurements and on a committee of the National Academies of Science. He has participated in several international missions on behalf of the International Atomic Energy Agency and, most recently, he travelled to Japan a month after the reactor meltdowns as part of a team that worked with physicians and emergency responders caring for victims exposed to radiation.

Andrew Karam is the author of 16 books and 20 scientific papers as well as 200 encyclopedia articles. He has also written several hundred articles, editorials, and essays for both professional and general audiences. He worked for the NYPD Counterterrorism Division as the Director of Radiological Operations.

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