You may have noticed our new Prop 65 labels on our product. Sorry if they are alarming. Fear not! Continue reading for perspective on the actual associated risk and reason for labeling.
Materials with ingredients on California's Prop 65 list include physical labeling in compliance with California law. Composition-based labeling provided as actual exposure risk is not quantified. Particulate exposure risk is low based on encapsulation in plastic. If exposing particles through abrasive processes like sanding, please seek proper PPE & ventilation to minimize particulate exposure. Vapor risk is generally low for PLAs, but other plastics like PC-ABS can introduce greater risk. Process & room conditions can also influence exposure. In general, please operate in a well-ventilated area and seek proper PPE as required.
This warning label is on any material with black or white pigments (carbon black and titanium dioxide). Pearl also contains titanium dioxide. These are industry standard additives and the risk is in particle form when not encapsulated in plastic. Glitter and other colors have no carcinogens to report. This is no different that everyone else's materials, we're just calling it out...
The carbon black all us filament manufacturers use is considered a carcinogen in powder form. A user's exposure to powdered carbon black is likely zero but it's the manufacturer's burden to prove exposure level. Instead of proving safe exposure level, we labeled based on composition. Unfortunately, this is mostly misleading, creating fear where there need not be any. Any chance of exposure would be in sanding or burning the filament to separate the carbon black. Again, carbon black is in everything so I understand this seems a bit over the top.
Again, the actual risk exposure related to titanium dioxide mirrors that of carbon black.
Our first goal with these labels is to comply with California law, but my hope would be to create awareness rather than alarm. I'm not sure these labels do that. This exercise has made us more aware of the risk when working with the dry ingredients so we can adapt our working conditions accordingly.
For our customers, the practical implication is a reminder of proper ventilation and protection from dust when sanding and fumes when printing. Carbon black and titanium dioxide is in everything around us. In fact, titanium dioxide is in particle form and free in the air in many cosmetics so there is a risk to using make-up, for example.
The style of communication California requires is more alarmist than educating. This is unfortunate because I expect the typical response is fear ceasing use or ignoring with continued use (neither of which is ideal), rather than education in assessing real risk and adapting how to use in a safe way.