Wednesday, April 22, 2015

n-Hexane, benzene, still troublesome in China

An interesting, sad Wired article about Chinese occupational exposure to industrial solvent and the difficulty surrounding getting health care after the injury from the exposure:
THEY CALLED IT “banana oil.” Long Li didn't ask what was in it. All she knew was that she was supposed to use it to clean cell phone screens, hundreds of them every hour. Fumes filled the air in the windowless room where she worked, in a three-story factory outside the southeastern China city of Dongguan. 
Long, the 18-year-old daughter of peasant farmers from Guizhou, was supposed to dip her rubber-gloved right index finger into the oil and then rub each screen for 10 to 20 seconds. The company—Fangtai Huawei Electronic Technology—gave Long and her coworkers paper masks, but they rarely used them. They were too hot, and anyway the women who worked there often exhaled onto the screens because the condensed moisture from their breath made cleaning easier. Long worked from 8 am until 11 pm, and as late as 4 am in the busy season. 
...But if working conditions were improving at Chinese factories, Long did not see it. Soon after she began working at Fangtai Huawei, her fingertips started tingling. After a few months, her feet and hands were numb. Long couldn't hold the screens properly. Her coworkers started getting sick too—Zi Renchun, a 25-year-old from Yunnan province, lost her appetite. Shang Jiaojiao, who had begun working at age 14, had joint pain and eventually could barely lift herself out of bed. By summer, some of the workers were collapsing. 
In mid-July, Long found herself unable to move her legs. “I was just lying on my bed all day and needed help to eat,” she says. Long ended up in a hospital in Guangzhou with more than 30 other Fangtai Huawei workers. Doctors found they'd been exposed to n-hexane, presumably in the “banana oil.” It's an industrial solvent that causes neurological damage at just 50 parts per million. Workers using it are supposed to wear respirators and operate in a ventilated area. As treatment, Long endured daily injections—she says they “hurt more than anything else in the world.” We interviewed her in a hotel a few blocks from the hospital; officials there wouldn't answer our questions or allow us to see her on the premises. Long still tries to stay cheerful. “When I cry,” she says, “I cry secretly.”
Another one that I'm rather horrified by, from the same article:
In 2007, when he was 20 years old, Ming Kunpeng began working at a factory then owned by Dutch company ASM International—a leading manufacturer of assembly equipment for computer chips, phones, and tablets. For two years, Ming cleaned motherboards with chemicals including benzene, a sweet-smelling and particularly effective industrial solvent and degreaser. It is also a carcinogen. Where people still use it, the International Labour Organization recommends wearing helmets with a face piece blowing clean air and gloves made of Viton, an expensive heat- and chemical-resistant fluoroelastomer. Ming Kunpeng says he was given only masks and standard gloves. 
In 2009 he was diagnosed with leukemia from benzene exposure, according to medical records. But as recently as 2013, changes to China's health care system continued to make health care untenable for him—and many others with work-related problems. When the family asked ASM for compensation, the company refused to pay, disputing the cause.  
A good reminder that chronic solvent exposure is bad (if you needed a reminder) and why the regulatory state (despite all of its many, many faults) manages to keep us from getting leukemia and other neurological damages.

(Is it really necessary to hand-clean screens and motherboards with industrial solvent? Surely there's a better way?)

UPDATE: DoD comments, and I reclarify what I meant above. (added "hand", which is what I was really getting at.) 


  1. "Is it really necessary to clean screens and motherboards with industrial solvent? Surely there's a better way?"

    Industrial solvent: The use of this term with a negative connotation is, in my opinion, equivalent to the use of toxins and chemicals. Does "industrial solvent" mean anything other than a liquid that dissolves substances and is used in an industrial process? Wouldn't we consider water to also be an industrial solvent?

    1. Actually, I agree that water is a very useful industrial solvent. But point taken.

  2. Industrial solvents are different from solvents for home use. Most solvents for home use are made to be relatively nontoxic on unprotected exposure (methylene chloride in paint strippers a likely exception), not terribly toxic on periodic exposure, or used in small amounts (nail polish remover). In contrast, solvents used in industry don't have those requirements - industry can use nontoxic or less toxic solvents (such as water), but the assumption for industrial solvents would be that they don't have to be so because people would not be exposed to them (the process is contained) or be exposed minimally, and that people who were likely to be exposed would have access to appropriate protective equipment, and they would be used on large scales in most cases. So, while it might not be true in particular cases, the correlation of toxicity with industrial solvent (as opposed to solvent for home use) isn't unreasonable.

    The implication of the term would be that the solvents used weren't for unprotected use, and they weren't. It's just that the companies using them didn't care about their workers, and so the protection that their use should have required wasn't employed.

  3. "n-hexane...causes neurological damage at just 50 parts per million"

    And the students who used to work next to me wondered why i was always complaining that they left their column fractions out on their benchtop to evaporate.