The International Council on Nanotechnology

Physicians link worker illness to nanoparticle exposure

A research paper released today in the European Respiratory Journal documents for the first time a clinical case in which a team of medical doctors concluded that exposure to nanoparticles was determined to have resulted in harm to workers. [The link is not live but an abstract is available here.] The medical case study documents in clinical detail the cases of seven women who were hospitalized for pulmonary health problems after workplace exposure to ~30 nm nanoparticles contained in or produced by the spraying of a polyacrylic ester paste. An extensive clinical evaluation was undertaken to determine the cause of the workers’ respiratory symptoms, which included shortness of breath, buildup of fluid in the chest cavity (pleural effusion) and around the heart (pericardial effusion) and itching on the face and arms. The clinical findings included nonspecific pulmonary inflammation, pulmonary fibrosis and foreign-body granulomas in the pleura. Ultimately, two of the women died from respiratory failure and others exhibited persistent lung dysfunction 20 months after first being hospitalized. The women’s clinical symptoms are consistent with the outcomes of animal studies in which nanoparticles have been intentionally introduced into the lungs.

The evidence for implicating nanoparticles in the Chinese factory incident is persuasive. The paper contains electron microscopy images of the fluid and lung tissues extracted from the patients that clearly show round nanoparticles or nanoparticle clusters of ~30 nm. The nanoparticles were found in the chest fluid and in cytoplasm and nucleoplasm of the pulmonary epithelial cells. Yes, these were nanoparticles, and yes, some nanoparticles may be able to gain access to parts of the deep lung that are less accessible to larger particles which the body more effectively filters out. Less clear is what the nanoparticles were composed of and whether they were intentionally introduced into the paste or created as a result of the spraying or heating processes. If the latter, then they were what we call “incidental” nanoparticles rather than the intentionally designed “manufactured” nanoparticles.

The exposures, which could not be quantified, took place over the course of between 5-13 months in which the workers operated a machine that converted a polyacrylic ester paste into tiny droplets and sprayed these droplets onto large boards used in the printing and decorating industry. The boards were then heated and dried with the resulting vapor removed via a gas ventilation unit on the machine.

Except the vapor wasn’t ventilated.
According to the article, the gas ventilator had broken 5 months before the onset of symptoms, which, when coupled with the lack of windows and closed door, meant that there was little air circulation and therefore no mechanism to remove the vapor from the workspace. Moreover, the only personal protective equipment available to the workers were cotton gauze masks, which would not be expected to filter out particles as small as ~30 nm. Even if the masks had been protective, they were worn only sporadically as the women appeared to have been uninformed about the possible toxicity of the materials to which they were exposed.
This almost certainly could have been avoided by the application of the “Golden Rule” of workplace safety: when you’re not sure of the hazards, do everything you can to minimize exposure. This is just the kind of industrial accident the GoodNanoGuide is intended to help prevent. For example, the page on liquid nanodispersion spraying controls describes the importance of ventilating the exhaust from the process and employing personal protective equipment as a secondary measure of protection. According to the latest research from the National Institute for Occupational Safety and Health, the 30-nm particles could have been blocked by an inexpensive, spray-paint respirator sold at your local home improvement store such as these or even these. It is possible to work safely with nanoparticles IF the hazards are recognized and the exposures limited.
What a tragedy.

Here are three important take-aways from this incident.
Workplace safety is of paramount importance wherever hazards are possible. When hazards are unknown or poorly understood, steps must be taken to reduce exposure to the hazard. In this case, this means first employing engineering controls such as ventilation of fumes and then relying on personal protective equipment such as respiratory masks but only as a secondary measure of protection. Such tools exist and could have prevented this tragedy if used correctly.

More investigation is needed to establish the facts surrounding the exposures so that similar incidents can be avoided. The evidence demonstrating that nanoparticles ended up in the workers’ lungs is compelling and persuasive. What is less well established is the type of nanoparticle found in the tissues and cells, the dose received by the workers and the mechanism of injury. It is not clear, for example, whether the nanoparticles themselves caused the injury or whether the combination of nanoparticles and other chemicals in the complex mixture resulted in an antagonistic effect. Regardless of these details, this work is a significant and well-documented clinical case study.

Research on and the development of tools for communication about occupational health issues associated with nanoparticles should be accelerated. Analysis of the ICON Nano-EHS database reveals a critical gap in nanomaterial research of relevance to occupational health as compared with research on nanotechnology environmental, health and safety research in general. So while knowledge about toxicity and hazard grows, understanding how to apply this knowledge in a practical occupational setting still presents a major challenge. While this study highlights a need for fundamental worker protections, better tools are also needed to communicate about potential risk along the supply chain, including during business-to-business transactions, so that consumers of all types have the information they need to handle nanomaterial-containing or nanomaterial-producing products safely. International trade agreements may be a mechanism for better enforcement of worker protections.

For more perspectives from an international group of experts, please click on over to Andrew Maynard’s 2020science blog.


Jennifer said...

Very helpful blog. Thank you, ICON!

Jaydee Hanson said...

One of the more interesting things , is that it seems that no one has asked prominent Chinese nanoreseachers what they think of this development. Chengyu Jiang - a molecular biologist at the Chinese Academy of Medical Sciences in Beijing published a paper in June on a class of nanomaterials used in nanomedicine. He is studying nanomaterials to see how they might "provide us with a promising lead for developing strategies to prevent lung damage caused by nanoparticles."

My point is that almost all of the discussion quotes only US or European researchers, when the Chinese have the largest number of chemical plants using nanomaterials. Unfortunately, the Chinese researchers have a lot of occupational illness data that the rest of us might not have access to.

Kristen Kulinowski said...

Thanks, Jennifer, for leaving a comment. Jaydee, you may recall that we interviewed two Japanese authors for our MWNT-asbestos backgrounder of 2008 and even had materials translated into Japanese. For this work, ICON did not have time to prepare a full-fledged backgrounder or contact the Chinese authors for comment. I agree fully that their perspective, and that of their colleagues in China, would be invaluable. If any read this blog, I encourage you to comment!

David Eckensberger said...

An interesting though alarming article - or better to say: result!

Still I think, one should see it critically, as this happend in China and we do not know what was has been going on around this fabric hall. I agree, that the coincidence of the ventilation failure and the beginning of complications is surely not by chance, but I think there are much more points to consider. Beginnig with the (in the end regarding 30 nm particles) completly useless masks, China is not renowned for high securtiy standards. There might be many other things triggering the problems - though the nanoparticles might be supporting and accelerating the progess of symptoms.
But in deed, there is increasing indication that researchers have to focus more on the aspects of nanoparticles' bioavailability.
Fortunately, there is a lot of research beginning in this field (just chek out recent articles in Journal of Apllied Toxicology and Environmental Science & Technology).

With kind regards, David

P.S.: Unfortunately, this comment denies my added links to the articles, so if you're interested, check out my article at euchems2010.wordpress.com

Kristen Kulinowski said...

Thanks for your comments, David. If the ICON Virtual Journal of Nano-EHS is missing any of the articles you refer to, please use the comment form at the VJ to alert us and we'll add them right away.

John Baker said...

Kristen, your analysis of the reports about the ERJ article is very helpful. We will be providing employee HSE training very soon for a CNT clean up project and this helps us prepare for any questions on this report. I conducted HSE assessments of several electronics and electrical equipment manufacturing facilites in China in 2003, and found quite a variation in management attitudes and conditions. Some appeared to be excellent (of course, they were expecting us as representatives of the foreign investors) and others were quite the opposite. Thanks for everything you do at ICON to share best practices in occupational health for engineered nanoparticles.

Jonathan said...

Amazing post really. especially the graph is really noteworthy.


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