Here is a fine example of how allow-list strategies are far superior to block-list:

Since Sept. 11, the government has taken very seriously the threat of attacks on the U.S. water supply. Federal law requires nearly all community water systems to assess their vulnerability to terrorism.

Big cities employ a range of safeguards against chemical and biological agents, constantly monitoring, testing and treating the water. But electronic protection systems can trace only the toxins they are programmed to detect, Lawler said.

Bluegills — a hardy species about the size of a human hand — are considered more versatile. They are highly attuned to chemical disturbances in their environment, and when exposed to toxins, they experience the fish version of coughing, flexing their gills to expel unwanted particles.

Nice. The fish monitor the quality of water by living in “known good” conditions. It’s usually an impossible race to try and keep up with detection of all the latest attacks, or known bad conditions, which is why an allow-list such as this is the preferable approach when possible.

I am reminded of fish I caught on a line when I was growing up. When I was older I returned to some of my favorite spots only to find warnings posted by the government about toxic levels of poison that had resulted from pesticide and herbicide runoff. I was told the infamous Agent Orange of Vietnam was still legal if you sprayed it on the backs of cattle to keep insects away. The rain would then wash the poison into the ground and rivers which fed our ponds and lakes. The areas had become toxic to fish and thus humans due to weak regulation of agricultural industries.

More information about the bluegill system can be found here:

The iABS monitors fish behavior using a pair of non-contact electrodes mounted above and below each of eight bluegills. As the fish move in the chamber and ventilate their gills, muscle contractions generate electrical signals in the water that are monitored by a computer. When abnormal fish behavior is identified, the iABS provides immediate alarm notification and can start an automated water sampler to permit follow-up chemical analysis.

So if local fish die as a result of weak environmental regulations, and the water quality has already been ruined by an environmentally hostile department of agriculture, the worry about terrorists putting toxins in the water and killing bluegills seems well-intentioned yet a little less pressing than the already present problems.

Should community water systems assess their vulnerability to all toxins, as I mentioned back in February, or just the ones from “terrorists”? Will homebuyers start to demand air and water quality records and tests prior to home purchase, to ensure a functioning security system that will protect their health?