High-fructose corn syrup rose from obscurity to ubiquity starting in the late 1970s, borne up by an informal public-private partnership between grain-processing giant Archer Daniels Midland and the federal government. For me, HFCS is at best a highly processed, lavishly subsidized, calorie-heavy, nutritional vacuum.

I recently visited a public high school in Boone, N.C. The main hall literally hummed with machines peddling variations on Coca-Cola’s formula for success: fizzy water with artificial flavor, artificial color, added caffeine, and a jolt of HFCS. Other machines displayed snack “foods” tarted up with HFCS. Why are we feeding our kids this crap, again?

Now comes news that makes even an HFCS cynic like me do a spit-take over my home-brewed morning coffee. Turns out that HFCS is commonly tainted with mercury — a highly toxic substance — according to a peer-reviewed report published by Environmental Health (abstract here; PDF of the must-read full text here.)

The Environmental Health study draws on samples of high-fructose corn syrup taken straight from the factory. But no one drinks the stuff straight. What about, say, cookies sweetened with HFCS? The Institute for Agriculture and Trade Policy plucked HFCS-containing products from supermarket shelves and tested them for mercury. The result?

Overall, we found detectable mercury in 17 of 55 samples, or around 31 percent

Traces of mercury turned up in name-brand products from makers including Quaker, Hunt’s, Manwich, Hershey’s, Smucker’s, Kraft, Nutri-Grain, and Yoplait.

That a ubiquitous industrial-food ingredient such as HFCS should be tainted by mercury is bad enough. But it gets worse. The FDA has apparently known about this since 2005 — and done nothing to publicize it or change it.

In 2005, EH study lead author Renee Dufault was an FDA researcher. At that time, she conducted the tests now cited in the EH report. Her results found mercury in 9 of 20 HFCS samples — 45 percent.

She doesn’t comment on why, but the FDA apparently did nothing with her results in the years since they emerged. She retired from the agency in March 2008 — and evidently decided to go public. She deserves praise for the decision to publish her work — essentially blowing the whistle on what looks like an egregious attempt to hide key information from the public.

So how does mercury work its way into our the food industry’s favorite sweetener? It finds its way into Pop Tarts and the like through the stunning array chemicals required to transform corn into a cane sugar substitute. (As you read the following list, marvel that the FDA recently ruled that manufacturers can label HFCS-sweetened foods "natural.") According the the EH study:

Several chemicals are required to make HFCS, including caustic soda, hydrochloric acid, alpha-amylase, gluco-amylase, isomerase, ilter aid, powdered carbon, calcium chloride, and magnesium sulfate.

Two of those charming-sounding chemicals — caustic soda and hydrochloric acid — can contain traces of mercury.

Caustic soda and hydrochloric acid are made through the same processes that produce chlorine. It can be done in one of two ways. The first involves pumping saltwater through a vat of mercury. The stuff produced this way is known as "mercury grade."

The second process involves no mercury. The industry is shifting to the second process, but the mercury style has by no means been phased out. According to IATP, "Today, the chlorine industry remains the largest intentional consumer (end user) of mercury."

So you’ve got this "mercury grade" caustic soda and hydrochloric acid floating around. Guess who’s using it? According to the EH study, "mercury grade caustic soda and hydrochloric acid are primarily used by the high fructose corn syrup industry."

Not only did the FDA fail to inform the public of HFCS’s mercury problem; food manufacturers that use HFCS may have been in the dark, IATP reports.

There is one hopeful tidbit from the highly disturbing Environmental Health and Institute for Agriculture and Trade Policy studies. Several years ago, then-Sen. Barack Obama introduced legislation that would have forced the chlorine industry to phase out mercury.

That bill failed. I hope the new Congress revives it. And I hope the Obama FDA investigates precisely why the agency sat on information that could have saved consumers from mercury exposure. The officials who made that decision — as well as the HFCS industry, led by Archer Daniels Midland — must be held to account.