Managing the Impact of Nanomaterials in Aerospace Manufacturing

As the aerospace industry continues to make improvements to safety, comfort and affordability of aircraft, nanomaterials are making their way into more elements of aircraft structure, electronics, glass, textiles and other components. While these materials provide tangible advantages in terms of weight, strength, speed and comfort, their effect on the humans that come into contact with them is still being studied and debated.

Scanning electron microscopy image from a dermal sampling of skin showing a carbon nanotube. (Bureau Veritas)
With dimensions between approximately 1 and 100 nanometers – about the size of a virus – nanomaterials have unusual physical, chemical and biological properties that can differ significantly from the properties of bulk materials, including single atoms or molecules. These differences enable the aerospace industry to do a number of things including: engineer aircraft structures that are flexible and adaptive; develop innovative energy generation and storage systems for air travel; and manufacture sensors that monitor virtually every element of air travel. However, these differences also create challenges for ensuring that an aerospace manufacturing workforce and those supporting its supply chain are not inhaling unhealthy concentrations of nanomaterials.

Published research studies, such as those conducted by the National Institute for Occupational Safety and Health (NIOSH), demonstrate that some nanomaterials have the potential to cause adverse human health effects. Occupational health risks associated with manufacturing and using nanomaterials have been under study for at least two decades and the understanding of their impact is still evolving. For example, inhalation toxicology studies of nanomaterial composites have shown a real possibility for lung inflammation and fibrosis.

Workers handling nanomaterials or products containing them may be at risk for inhaling fine dusts or aerosols, either during the production of the nanomaterial or during the manufacture or use of products containing nanomaterials. Published exposure assessments, such as those conducted by NIOSH, indicate the need for high-integrity process containment and controls when handling nanoparticles.

However, the number of nanomaterials already in commerce far exceeds NIOSH’s ability to a) characterize the potential hazards associated with worker exposures and b) establish safe exposure levels. Organizations developing and using innovative nano-enabled products must develop internal processes to manage the potential risks to their enterprise. Such risks will not only affect the health of their workforce, but also delay or impede their ability to commercialize nano-enabled products and extend far beyond those that are normally associated with chemical exposures in the workplace.

Developing a Risk Management Approach

An integrated, enterprise-wide risk management approach is essential to ensure that occupational risk is controlled throughout the supply chain; from those that supply the nanomaterials, to the technology manufacturers using the materials, and on to those developing and using the innovative products this technology supports.

The first step is to establish a clear risk control policy. An executive positioning statement addressing all activities, from procurement of the nanomaterial or intermediate product, to production, and including distribution and use, clearly demonstrates management’s commitment to ensuring worker health throughout the supply chain. Worker health and safety exposure controls may not be considered during product, process, and facility design because regulations requiring the control of worker exposures to nanomaterials do not yet exist, and codes and standards to include appropriate engineering controls into the design of facilities, processes, and equipment have not been established. However, a wealth of authoritative guidance is available, such as “Current Strategies for Engineering Controls in Nanomaterial Production and Downstream Handling Processes (NIOSH Pub. 2014-102),” and “General Safe Practices for Working with Engineered Nanomaterials in Research Laboratories (NIOSH Pub. 2012-147).”

High resolution transmission electron microscopy image of a carbon nanotube. (Bureau Veritas)
Next, allocate appropriately-skilled resources, such as industrial hygienists, that can identify and characterize the nanomaterials hazards. Nanomaterial hazard characterization is one of the most challenging tasks due to the unusual physical, chemical, and biological properties that can affect the toxicity of the material if it enters the body through the lungs, by ingestion, or through the skin.

Assessing exposure risks to nanomaterials begins with the collection of data about the workplace, workforce, and the nanomaterials and nano-enabled substances. The workplace is characterized by understanding the process equipment containment including: the ventilation system exchange rates and filtration; the air, materials and people movement throughout the facility; local exhaust ventilation and dust collection systems; the room finishes where nanomaterials will be handled; and areas for workers to put on and remove personal protective equipment and clothing. The workforce assessment must also define the tasks performed by each worker and how they might be performed differently by various individuals, which will significantly impact worker exposure risks.

The final contributor to the exposure risk is the nanomaterial itself. Again, identifying the presence of a nanomaterial or nano-enabled products may be difficult since hazard communication and labeling requirements are still in development, and health effects data on most nanomaterials are still lacking.

In the absence of nanomaterial-specific data, progress is being made on developing a process for grouping these un-studied nanomaterials with other materials. They are categorized as either nanomaterials with adequate toxicity information to develop occupational exposure limits (OELs), or normal-size materials with a similar mode of action, toxicity, and physical-chemical properties to establish acceptable ranges of occupational exposures, commonly referred to as occupational exposure bands (OEBs). Combined with the workplace and workforce characterization, these nanomaterial OELs and OEBs allow the industrial hygienist to identify the job tasks for each job title with potential exposure risks above the OEL or OEB, or those that result in uncertain assessment of risk.

It is also vital that the enterprise risk management system include the organization’s manufacturing and distribution supply chain. The unique hazards and rapid development of new information about the toxicity of nanomaterials means the supply chain will look to the manufacturer’s organization for information on how to safely handle nanomaterials or nano-enabled products. Protecting the health and safety of the supply chain workers will also ensure that preventable health and safety issues won’t disrupt the business flow. Monitoring supply chain activities, disseminating new information about nanomaterial hazards and appropriate risk-based controls, and measuring health and safety performance globally, will create business value and ensure the health and safety of all the workers potentially exposed to nanomaterials or nano-enabled products.

Finally, the enterprise risk management system must seek out opportunities for continual improvement, an important step due to the rapidly expanding number of nanoparticles and nano-enabled products, as well as the publication of new toxicity data.

Third-Party Expertise

Manufacturers new to using nanomaterials in their construction process should consider using experienced third-party industrial hygiene experts who can help design and implement a holistic risk management approach for the handling of nanomaterials and nano-enabled products. These experts pride themselves on providing certified and qualified risk management support and services including: material characterization, exposure limit and analytical method development, exposure assessment, exposure control, waste minimization and management, and supply chain assessment. Leveraging a thirdparty expert also gives manufacturers added assurance that they will be able to protect workers from nanomaterial exposure to the very best of their ability.

Supporting the aerospace industry’s leadership in using advanced materials and advanced manufacturing methods to achieve our vision of commercial air travel is both exciting and challenging. It requires that risk be assessed and managed throughout the enterprise, keeping workers safe and healthy, and supporting a company’s ability to bring new technology to market.

This article was written by Donna S. Heidel, CIH, FAIHA™ and John Baker, CIH, Bureau Veritas (New York, NY). For more information, Click Here .