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Now, the contaminant that leaked into the Elk River was a chemical called MCHM, and officials in West Virginia have promised to investigate how it might affect the public and the environment. That prompted NPR's Daniel Zwerdling to ask why didn't they know that before?
DANIEL ZWERDLING, BYLINE: Scientists do know a few things about MCHM. I went online and got a copy of a manufacturer's safety data sheet. It's says, warning, exclamation mark, harmful if swallowed, causes skin and eye irritation. OK, but now people want to know could there be any long-term effects from the huge spill and here's what the company's safety data sheet says about that.
Mutagenicity. In other words, does the chemical cause mutations? No data available. Carcinogenicity, no data available. Reproductive toxicity, no data available. If we could look at most chemicals and industry storage tanks around the country, have scientists studied most of them to know if they're safe or not?
RICHARD DENISON: The unfortunate answer is no.
ZWERDLING: Richard Denison is a biochemist with the Environmental Defense Fund. He's served on government and industry advisory boards.
DENISON: The vast majority of industrial chemicals have never been required to be tested for safety.
ZWERDLING: And to understand why, you have to look back to the 1970s. Congress passed the first major laws, saying we should crack down on water pollution and protect workers from dangerous chemicals. And then public health specialists said, wait a minute, how can we protect workers and the environment when we hardly know anything about most chemicals used in the industry?
So Congress passed the Toxic Substances Control Act. It's nicknamed TSCA. Nicholas Ashford(ph) says, this was historic.
NICHOLAS ASHFORD: This would be the first time that industrial chemicals across the board could be subjected to testing rules and placing the burden on industry to undergo the testing for safety.
ZWERDLING: Ashford was chairman back then of federal taskforce that advised the government on toxic chemicals. TSCA basically said, look, industry has already been using more than 60,000 chemicals. Let's let industry keep using them unless the Environmental Protection Agency finds evidence they could be harmful. Richard Denison says, there's a problem.
DENISON: And that sets up a catch-22.
ZWERDLING: The way Congress wrote the law, EPA can order companies to study old chemicals only if EPA has evidence that the chemicals might be dangerous. But it's hard for EPA to get that evidence unless the industry does the studies in the first place.
DENISON: It's kind of like looking for your keys at night in a parking lot and you look only under the lamps because that's where the light is better. But in fact, the vast majority of chemicals are out there in the darkness.
ZWERDLING: Still, some scientists have managed to take a closer look at some old chemicals in the darkness and they found big problems. For instance, practically every sofa in America used to contain a flame retardant called PBDEs. Then, in the 1990s, researchers started finding them in practically every person they tested, in their blood, in their fat, and in breast milk.
And studies show they have powerful impact on hormones. Industry voluntarily phased out the chemicals. Some members of Congress, Republican and Democrats, say it's time to overhaul the TSCA law. And the spokesperson for the chemicals industry agrees.
Anne Womack Kolton is vice president of the American Chemistry Council. She says many chemicals are well-known and safe. But she says it's also true that scientists keep being able to measure chemicals in the environment at lower levels, and finding they can have effects. So she wants Congress to pass a better law.
ANNE WOMACK KOLTON: We can increase transparency. We can give EPA the authority it needs. And we can give all consumers greater confidence that the chemicals in the products they rely on every day are safe for that use.
ZWERDLING: The head of EPA said recently that she hopes Congress will overhaul the TSCA law. Gina McCarthy said the way the law works now, it's broken and ineffective.
Daniel Zwerdling, NPR News.
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