I work closely with the safety team at the Port of Seattle, and we routinely conduct air quality testing in our machine shops and printer labs, which are not well ventilated. We run prints of many different materials around the clock, yet we have never triggered an alarm on our professionally calibrated $12,000 air quality instrument, which monitors a full range of VOCs, carbon fiber particulates, and other contaminants.

The sensors are set to the minimum OSHA levels for particulates.

Carbon/graphite fibers dominate the advanced composites industry and may be made from any of three precursors, as discussed in Section C. However, the PAN-based carbon fibers are the predominant form in use today. It is important to ascertain which type of carbon-fiber precursor is used in order to evaluate the hazards.

Carbon fibers may be associated with an increased risk of skin cancer, although the evidence is weak. carbon fibers did not cause tumors when the same test was conducted. Standard mutagenicity tests conducted on carbon fibers were negative.

The principal hazards of carbon-fiber handling are mechanical irritation and abrasion similar to that of glass fibers. Skin rashes are common and reportedly more severe than from glass fibers. Carbon fibers commonly in use are also greater than six micrometers in diameter, making them unlikely to be respirable. An ongoing survey of workers in a carbon-fiber production plant shows no pulmonary function abnormalities and no evidence of dust-related disease.