The Washington Post has an eye-opening story this morning on “secret chemicals” concealed from everyone but a few EPA officials under a dubious law meant to protect inventions.

The paper writes that one in five of the 84,000 chemicals used in the U.S. is exempt under the law from disclosure of its name, properties, and oftentimes even who the manufacturer is.

The identities of the chemicals are known to a handful of EPA employees who are legally barred from sharing that information with other federal officials, state health and environmental regulators, foreign governments, emergency responders and the public.

Say what?

The Post calls it “a little-known federal provision.” I didn’t know about the 33-year-old law, did you? Where has the press been on this, if not? The Post quotes and credits “an advocacy organization that documented the extent of the secret chemicals through public-records requests from the EPA.”

Here’s what it found:

Of the secret chemicals, 151 are made in quantities of more than 1 million tons a year and 10 are used specifically in children’s products, according to the EPA.

And:

Although a number of the roughly 17,000 secret chemicals may be harmless, manufacturers have reported in mandatory notices to the government that many pose a “substantial risk” to public health or the environment. In March, for example, more than half of the 65 “substantial risk” reports filed with the Environmental Protection Agency involved secret chemicals.

The Post shows how this works with a good anecdote of a nurse gravely sickened (it seems) by chemical exposure to something called ZetaFlow:

Her liver was failing and her lungs were filling with fluid. Behr said her doctors diagnosed chemical poisoning and called the manufacturer, Weatherford International, to find out what she might have been exposed to.

Weatherford provided safety information, including hazards, for the chemical, known as ZetaFlow. But because ZetaFlow has confidential status, the information did not include all of its ingredients.

Mark Stanley, group vice president for Weatherford’s pumping and chemical services, said in a statement that the company made public all the information legally required.

Reporter Lyndsey Layton also makes good use of an anecdote with something called “Firemaster 550” made by Chemtura Corporation that has a similar ingredient to the recently banned DEHP.

But while this is a good story and the Post is good to put this issue on page one, it seems a bit short-armed. The story needed more space.

Let’s hope the Post and others follow up on it with a big spotlight.

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Ryan Chittum is a former Wall Street Journal reporter, and deputy editor of The Audit, CJR's business section. If you see notable business journalism, give him a heads-up at rc2538@columbia.edu. Follow him on Twitter at @ryanchittum.