Nickel Nanoparticles: A Case of Sensitization Associated with Occupational Exposure

In an article published online May 8, 2014 by the American Journal of Industrial Medicine, researchers W. Shane Journeay, Ph.D., M.D., and Rose H. Goldman, M.D., MPH, report the case of a worker who developed sensitization to nickel when working with nickel nanoparticle powder.

According to the details of the case presented by Journeay and Goldman: “A 26-year-old female chemist formulated polymers and coatings usually using silver ink particles.  When she later began working with nickel nanoparticle powder weighed out and handled on a lab bench with no protective measures, she developed throat irritation, nasal congestion, ‘post nasal drip,’ facial flushing, and new skin reactions to her earrings and belt buckle which were temporally related to working with the nanoparticles.”The abstract continues, “Subsequently she was found to have a positive reaction to nickel on the T.R.U.E. patch test, and a normal range FEV1 that increased by 16% post bronchodilator.”¹ 

Journeay and Goldman add valuable new scientific evidence to the ongoing base of knowledge about the need for a proactive approach to addressing potential occupational health and safety implications of nanomaterials in the burgeoning global nanotechnology industry.   Case studies by alert clinicians are important to NIOSH and its partners in assessing risks posed by occupational exposure to nanomaterials, and in making recommendations for appropriate risk-management practices. 

The basic association between exposure to nickel and the worker’s symptoms is not surprising.  An ample body of scientific evidence associates exposure to nickel in traditional forms with risk of respiratory and skin sensitization.  The immediate question raised by the case study is this:  Other factors being equal, notably in this instance the uncontrolled nature of the worker’s exposure as described by the authors, does exposure to nickel nanoparticle powder increase the risk of sensitization above the risk posed by exposure to traditional forms?

Journeay and Goldman note the challenges that scientists face in answering that question.  Their description and discussion of the case highlight important factors from which scientists can make reasonable assumptions, and they also note gaps in knowledge that make it difficult to proceed from reasonable assumptions to confident conclusions.    

For example, based on available data, it would be reasonable and prudent to assume that nanoscale nickel — with a greater absolute particle number per gram and a greater total specific surface area — would be more potent than microscale nickel.  However, without knowing more about factors for which data still are lacking in this relatively young area of health research, such as  the processes through which nickel at the nano-scale may influence adverse reactions, science is challenged to say unequivocally that this would be the case, the authors suggest.  

As researchers and practitioners engage these issues, we find some important take-away messages from the new study:

• It is important to take precautionary and protective measures as scientists learn more about the properties and potential effects of nanomaterials, including any changes in the known effects of the material in moving from traditional to nano-scale forms, such as, in this case, nickel.
• The authors very correctly point out that there needed to be better exposure controls, and in particular, attention to the implications of exposure to nickel in the nanoparticle powder form.  Because the available data do not allow scientists to understand, with confidence, potential cause-and-effect relationships between the exposure and outcomes in ths case, they also correctly state  that the toxicology of nanomaterials needs to continue to be investigated.   .
• Importantly the the new report highlights the importance of conducting a new hazard assessment when nanoscale constituents are first introduced into the workplace.  With a greater absolute particle number per gram and a greater total specific surface area, nanoscale constitutents substituted for their macroscale counterparts increase the potential for occupational health risks .

Journeay and Goldman’s observations underscore the importance of prudent action, to have hazard and risk analysis, communication, and management practices keep pace with the well-established move in materials chemistry to the nano scale.  Such action is consistent with NIOSH’s recommendations for safe nano management in the workplace. 

As resources to help practitioners identify and use appropriate protective measures, the paper references NIOSH’s cornerstone documents – General Safe Practices for Working with Engineered Nanomaterials in Research Laboratories and Current Strategies for Engineering Controls in Nanomaterial Production and Downstream Handling Processes.  These and other resources can be found on our nanotechnology topic page.  If you have comments relating to the issues raised in the paper by Journeay and Goldman, we welcome feedback on this blog.

Charles L Geraci, PhD; Paul Schulte, PhD; Vladimir Murashov, PhD

Dr. Geraci is a Supervisory Physical Scientist in the NIOSH Education and Information Division and is the Coordinator of the Nanotechnology Research Center.

Dr. Schulte is the Director of the NIOSH Education and Information Division and Manager of the Nanotechnology Research Center.

Dr. Murashov is a Special Assistant for Nanotechnology to the NIOSH Director.

¹ Journeay and Goldman, “Occupational Handling of Nickel Nanoparticles: A Case Report,” Am. J. Ind. Med. (published before inclusion in an issue), p.  1.