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Recent studies have shown that high concentrations of ultrafine particles can be emitted during the 3D printing process. This study characterized the emissions from different filaments using common fused deposition modeling printers. It also assessed the effectiveness of a novel engineering control designed to capture emissions directly at the extruder head. Airborne particle and volatile organic compound concentrations were measured, and particle emission rates were calculated for several different 3D printer and filament combinations. Each printer and filament combination was tested inside a test chamber to measure overall emissions using the same print design for approximately 2 h. Emission rates ranged from 0.71 × 10 7 to 1400 × 10 7 particles/min, with particle geometric mean diameters ranging from 45.6 to 62.3 nm. To assess the effectiveness of a custom-designed engineering control, a 1-h print program using a MakerBot Replicator+ with Slate Gray Tough polylactic acid filament was employed. Emission rates and particle counts were evaluated both with and without the extruder head emission control installed. Use of the control showed a 98% reduction in ultrafine particle concentrations from an individual 3D printer evaluated in a test chamber. An assessment of the control in a simulated makerspace with 20 printers operating showed particle counts approached or exceeded 20,000 particles/cm 3 without the engineering controls but remained at or below background levels (< 1000 particles/cm 3 ) with the engineering controls in place. This study showed that a low-cost control could be added to existing 3D printers to significantly reduce emissions to the work environment.

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Recent studies have reported emission rates of up to 10 12 ultrafine particles/min from fused filament fabrication three-dimensional printers when operated in unventilated or minimally ventilated test chambers. However, in these studies, there are no data to relate this rate to airborne concentrations in a manufacturing environment. An assessment of particle exposures of workers was conducted at a three-dimensional printing shop using multiple fused filament printers with unfilled and carbon nanotube and/or carbon nanofiber-infused polyetheletherketone filaments. The study simultaneously evaluated emissions in two environments: (1) in a field portable test chamber with one threedimensional printer and (2) in the manufacturing area with multiple printers in use. Emission rates were calculated for a variety of filaments and ranged from 1.21 to 33.5 × 10 11 particles/min, with geometric mean diameters ranging from 11.4 to 33.3 nm. The emission rates estimated by a scanning mobility particle sizer were much lower than from the fast mobility particle sizer due to differences in the lower size resolution. Samples collected in the chamber and manufacturing area by thermophoretic sampling included free (no polymer) carbon nanotubes and nanofibers and their bundles. The company reportedly never handled free carbon nanotubes or nanofibers, and prior research has indicated that the release of free nanomaterials through three-dimensional printing or mechanical action is highly unlikely. This presents the possibility that these materials are being released from the matrix during use or that these materials were brought into the facility through the supply chain, or by other means.

Objective To evaluate the mortality experience among 3,199 workers employed 1951–1976 at a phosphate fertilizer production plant in central Florida with follow-up through2011. Methods Cause-specific standardized mortality ratios (SMRs) for the full cohort were calculated with the U.S. population as referent. Lung cancer and leukemia risks were further analyzed using conditional logistic regression. Results The mortality due to all-causes (SMR = 1.07, 95% confidence interval [CI] 1.02–1.13, observed deaths [n] = 1,473), all-cancers (SMR = 1.16, 95%CI 1.06–1.28, n = 431), and a priori outcomes of interests including lung cancer (SMR = 1.32, 95%CI = 1.13–1.53, n = 168) and leukemia (SMR = 1.74, 95%CI = 1.11–2.62, n = 23) were statistically significantly elevated. Regression modeling on employment duration or estimated radiation scores did not show exposure–response relation with lung cancer or leukemia mortality. Conclusion SMR results showed increased lung cancer and leukemia mortality in a full cohort of the phosphate fertilizer production facility. There was, however, no exposure–response relation observed among cases and matched controls.