3D printed objects may be toxic: study

Parts produced by some commercial 3D printers may be toxic, according to a new study that raises concerns about how to dispose of parts and waste materials from the devices which are becoming increasingly popular.
Researchers at the University of California, Riverside studied two common types of 3D printers - one that melts plastic to build a part, and another that uses light to turn a liquid into a solid part.
They found that parts from both types of printers were measurably toxic to zebrafish embryos, and parts from the liquid-based printer were the most toxic.
They also developed a simple post-printing treatment - exposure to ultraviolet light - that reduced the toxicity of parts from the liquid-based printer.

The study comes as the popularity of 3D printers is soaring, researchers said.
Printers that use melted plastic are currently available for as little as USD 200, and the liquid-based printer used in this study can be bought for less than USD 3,000, they said.

Researchers, including William Grover, an assistant professor of bioengineering in the Bourns College of Engineering and graduate student Shirin Mesbah Oskui, noticed that zebrafish embryos die after exposure to parts from the 3D printer.
They then decided to test the toxicity of printed objects from the two types of 3D printers.
Researchers used two commercial 3D printers in their study, a Dimension Elite printer made by Stratasys (which uses melted plastic to build parts) and a Form 1+ stereolithography printer made by Formlabs (which uses liquid resin to make parts).

She used each printer to create disc-shaped parts, about an inch in diameter. Then she placed the discs in petri dishes with zebrafish embryos and studied survival rates and hatch rates and monitored for developmental abnormalities.
While the embryos exposed to parts from the plastic-melting printer had slightly decreased average survival rates compared to control embryos, the embryos exposed to parts from the liquid-resin printer had significantly decreased survival rates, with more than half of the embryos dead by day three and all dead by day seven.
And of the few zebrafish embryos that hatched after exposure to parts from the liquid-resin printer, 100 per cent of the hatchlings had developmental abnormalities.

Oskui also studied the methods for reducing the toxicity of parts from the liquid-resin printer. She found that after exposing the parts to ultraviolet light for one hour, the parts are significantly less toxic to zebrafish embryos.
The study was published in the journal Environmental Science and Technology Letters.