Advancements in science allow us to see more of the world around us, but often raise more questions than answers. Such is the case with engineered nanoparticles, and the dilemma of how “standard industrial hygiene practices” apply to a potential hazard that isn’t yet fully understood.
Little particles, big question marks
Nanomaterials are defined by the Centers for Disease Control and Prevention as “engineered structures, devices and systems that have a length scale between 1 and 100 nanometers.” (A nanometer is one-billionth of a meter.) Because they’re used in a range of products, including stain-defying textiles, consumer electronic components, fuel additives and cancer drugs, employees at chemical plants, pharmaceutical laboratories, manufacturing facilities, construction sites and medical facilities are all at risk of exposure through inhalation, skin contact or ingestion.
While some adverse effects of nanoparticle exposure have been acknowledged – the National Institute for Occupational Safety and Health has named inhaled titanium dioxide nanoparticles as a “potential occupational carcinogen,” and found that some nanoparticles can penetrate cell membranes and cause damage, by and large the “occupational health risks associated with manufacturing and using nanomaterials are not yet clearly understood,” according to the Centers for Disease Control and Prevention (CDC).
Because nanotechnology is such a new and rapidly developing field, regulatory agencies are playing catch-up on two fronts: determining how to measure the occupational safety risks of nanomaterials, and determining how existing safety standards might apply to them.
Challenging conventional PPE
Right now, there are only a couple established occupational exposure limits for nanomaterials – for respirable titanium dioxide nanoparticles and carbon nanotubes and nanofibers. As such, the choice of personal protective equipment (PPE) such as respirators and gloves is often based on “conventional chemical hygiene criteria.” But there are questions as to whether conventional measures apply to the nano-world. A Canadian study, published in July, found that a N-95 respirator failed to screen out nanoparticles at the rate mandated by National Institute for Occupational Safety and Health certification standards, when airflow rates were comparable to a worker’s inhalation during heavy activity. A separate study, also funded by Quebec’s occupational safety and health agency, found that nanomaterial suspended in liquid could penetrate through nitrile, latex, and neoprene gloves, and powdered nanomaterials could penetrate gloves that underwent “mechanical stress” to simulate workplace wear-and-tear.
An evolving field
According to the researchers, findings such as this could lead to revised safety standards – such as enhanced respirators, filters and gloves, although regulations will likely continue to change as the use and manufacturing of nanomaterials continues to expand across multiple industries, exposing more workers to potential health threats.