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hexavalent chromium

More on metal recycling

The Chron has a followup story on metal recycling and hexavalent chromium.

Houston air experts plan to deepen their investigation into the air outside metal recycling companies after their measurements showed – apparently for the first time – that the businesses could be a source of potent fumes known to cause cancer.

“We are searching for money for more in depth testing, and also to get a feeling for what good controls would be,” said Loren Raun, an environmental statistician at Rice University, who works with the city of Houston.

[…]

Now the nation’s fourth largest city plans to expand its investigation of communities where the air may be affected. This week the Bureau of Pollution Control and Prevention’s mobile air monitoring lab returns to service following maintenance. On one of its first assignments, it will go to Holmes Road Recycling in the south of the city. Managers there are about to test a new vacuum system that operates while a worker is torching: It pulls smoke through a cyclone system to remove particles.

“In theory, it should make a significant difference in smoke and particles from any facility using the equipment properly,” said Don Richner, an analytical chemist with the Bureau of Pollution Control and Prevention.

If the new device makes a difference, the city could encourage other recyclers to employ it.

Another result of the testing is that Houston officials are questioning whether recyclers are exempt from the requirement to obtain air pollution permits. Businesses that pollute below a certain threshold are allowed to operate under what’s known as “Permit by Rule,” in which they state emissions are low. Pollution bureau chief Arturo Blanco said authorities will ask for proof.

Rice University’s Raun says researchers hope to return to the plants to test at a distance of one or two blocks. “We want to get a feel for what people farther out in the neighborhood are exposed to,” she said.

This would address a question raised by scientists that hexavalent chromium converts quickly to a less dangerous form of the metal. The city is collaborating with community groups, the University of Texas and Rice University in an application for a federal grant to pursue that research.

Background here. This sure seems like the sort of thing for which grant money ought to be granted. It’s groundbreaking research, and it could affect the way the EPA calculates the risks of air pollution. I look forward to seeing what their further tests find out.

Recycling pollution

This is unfortunate.

The calls to the city of Houston’s 311 help line came in the early morning and the middle of the night – complaints of red smoke, yellow smoke, explosions, fire, a child having trouble breathing.

Reports like these – 189 of them over the last five years – led Houston air authorities to discover a previously unrecognized and dangerous source of air pollution: metal recyclers and car crushers, according to interviews and documents obtained by the Houston Chronicle.

The smoke comes from cutting metal with torches and from fire when vehicle gas tanks aren’t drained properly. Explosions can occur when propane tanks are fed into the maw of the crushers.

Descriptions of shattering noise, cracked walls and smoke were significant enough that the city had to “dedicate a good amount of effort responding to these complaints,” said Arturo Blanco, chief of the city’s Bureau of Pollution Control and Prevention.

Subsequent testing outside five Houston metal recycling operations found dangerous levels of hexavalent chromium. Chrome VI, as it’s also called, is a high priority for air experts.

“People were complaining about smoke, and it turns out there were carcinogenic metals,” said Loren Roan, an environmental statistician at Rice University. “And we found them only around these facilities, not in other areas we tested, not even in other industrial areas of the city.”

When inhaled, hexa­valent chromium is deposited in the lungs, can penetrate cells and cause free radicals, which damage DNA, ultimately causing lung cancer. When California gained the authority to regulate air pollution hazards in the 1980s, hexavalent chromium shared top priority, along with benzene. The state considers Chrome VI one of the most potent carcinogens known.

[…]

Houston appears to be the first to examine metal emissions from the industry, and in so doing may have flagged a national problem. The Environmental Protection Agency does not regulate the facilities, though there are now 6,000 of them in the United States, according to Joe Picard, chief economist with the Institute of Scrap Recycling Industries Inc.

You can see a map of metal recycling locations here – the east side is particularly full of them, with the stretch of 59 between I-10 and the North Loop being a hot spot. Clearly, this is something that is going to require action. I’m certain there are plenty of opportunities to do this in a way that creates less hazardous by-product, but such innovation is unlikely to come without external pressure, which is to say government regulation. If that makes metal recycling more expensive, then so be it. We’ll figure out how to adjust. Recycling is necessary, but so is not creating hazardous emissions. We have to be able to do both.