Radioactive Shrimp

But I do have a pretty good idea what happened by which I understand the established processes and how they fail. The specific source of the Cs-137? Not a specific clue other than “Not the food irradiation facility in Indonesia. If they’d lost encapsulation/control of their irradiator source, we’d be in Goiânia incident territory. That would be a much more serious radiological incident we’d have heard about.”

It is easiest to work this backward. This is all theory, understanding of processes, not necessarily what happened. I often feel like Mr. Finch in situations like this.

The FDA issued a recall notice for several lots of shrimp on sale at Walmart. This is what the FDA is supposed to do for suspect foodstuffs, tell stores to pull it and people not to eat it. Whether you think they did a good job communicating on any given recall is always up to debate. But this begs the next set of questions:

FDA recall notices don’t do detailed information to answer questions like that. They are strictly information to stop sale and consumption of suspect products; we don’t even need to know for sure there’s Cs-137 contamination for every bag of shrimp, just suspect that there might be on ANY of them. That’s good enough to do a recall. They’re the tip of the information, investigation, and logistics iceberg and there was a whole lot going on before this notice was issued and likely still ongoing.

And that turns into a question of logistics systems and customs controls, specifically CBP’s portal monitoring program. We have passive portal radiation monitors at major ports of entry and minding the roads & rails leaving them to look for gamma emitters (as that’s the easiest to detect at scale and at distance). And we are exceptionally good at detecting Cs-137 because that’s what we calibrate all our detectors to. There are also monitors at the originating shipping ports for products coming our way as they’re the ones we gave money to so they’d improve their security and monitoring, so often stuff gets caught before it even gets near the American market. Doing that interdiction is what the C in CBP, Customs, is for even if the agency seems rather focused on the BP part lately. So, how did they miss this?

Portal monitoring is not 100%. Our inspection regime may be charitably described as a “statistical sampling of containers with an eye for outliers”. Passive monitoring is good, reduces effort, and lets you inspect more things, faster. Buuuuut not every path through a port is monitored, sometimes there’s a signal but the container contents shield it enough to be under the minimum detection limit, the monitors are prone to breaking, they need regular calibration which can also take them out of service, but The Tempo (the speed of containers coming off ships) never, ever stops. The ports make money by number of containers processed so they have no incentive to slow down and no one likes to spend money nor finds honor in doing maintenance. So things slip through, but obviously we did notice the Cs-137 since there was still a recall. What happened?

The better question is “When did we notice it relative to this particular shrimp product shipment?” Because of the statistical sampling nature of inspection, there is a very good chance we didn’t notice a crapped up transportainer on it’s first pass through a port, maybe not even the second. There is a non-zero chance that contaminated items were noticed by a highway/railway radiation monitor downstream of the port run by DOE/DHS/DOD who then sent up a flag to trace back the truck to their point of origin. That sets Date of Discovery. You then pull all the paperwork on this transportainer to figure out the last time it was actually screened by a portal monitor and found to be clean. That sets the other end of the time window. Between those two dates, you pull the manifests of everything that was shipped in that transportainer to see if you can determine what crapped up the container and wasn’t noticed until the Date of Discovery. This narrows the time window a little bit, so then you look at all the other shipments in that window to see what else might have suffered cross-contamination that you need to chase down. And if you see a food product, shit, that’s a call to the FDA.

Where did the Cs-137 come from in the first place in that transportainer? Why was it badly contained enough to contaminate things? Not questions I can answer but I’m sure folks are working real hard on that. It’ll be annoying if it’s the Camorra’s fault again. Also, that long discussion was a pre-supposition that its a cross-contamination issue in shipping, not in catch and processing of shrimp. That’s less likely to have an opportunity of Cs-137 contamination, particularly uptake from the environment. Cs-137 will kill the shrimp you eat just as easily as it will you if you eat enough, so “shrimp fished from an illegal rad waste dump” is not a particularly plausible pathway. Cross-contamination from the shrimping boat itself? Cross-contamination in the processing of the shrimp? Other than food irradiation, not a lot of call of Cs-137 in the shrimping industry.