We’ve all heard stories of the dangers of 3D printing, with fires from runaway hot ends or dodgy heated build plates being the main hazards. But what about the particulates? Can they actually cause health problems in the long run? Maybe, if new research into the carcinogenicity of common 3D printing plastics pans out.

According to authors [CheolHong Lim] and [DongSeok Seo], the research covered in this paper was undertaken because of reports of rare cancers among Korean STEM teachers, particularly those who used 3D printers in their curricula. It was thought that only long-term, continued exposure to the particulates generated by 3D printers could potentially be hazardous and that PLA was less likely to be hazardous than ABS. The study was designed to assess the potential carcinogenicity of both ABS and PLA particulates under conditions similar to what could be expected in an educational setting.

To do this, they generated particulates by heating ABS and PLA to extruder temperatures, collected and characterized them electrostatically, and dissolved them in the solvent DMSO. They used a cell line known as Balb/c, derived from fibroblasts of an albino laboratory mouse, to assess the cytotoxic concentration of each plastic, then conducted a comet assay, which uses cell shape as a proxy for DNA damage; damaged cells often take on a characteristically tailed shape that resembles a comet. This showed no significant DNA damage for either plastic.

But just because a substance doesn’t cause DNA damage doesn’t mean it can’t mess with the cell’s working in other ways. To assess this, they performed a series of cell transformation assays, which look for morphological changes as a result of treatment with a potential carcinogen. Neither ABS nor PLA were found to be carcinogenic in this assay. They also looked at the RNA of the treated cells, to assess the expression of genes related to carcinogenic pathways. They found that of 147 cancer-related genes, 113 were either turned up or turned down relative to controls. Finally, they looked at glucose metabolism as a proxy for the metabolic changes a malignant cell generally experiences, finding that both plastics increased metabolism in vitro.

Does this mean that 3D printing causes cancer? No, not by a long shot. But, it’s clear that under lab conditions, exposure to either PLA or ABS particulates seems to be related to some of the cell changes associated with carcinogenesis. What exactly this means in the real world remains to be seen, but the work described here at least sets the stage for further examination.

What does this all mean to the home gamer? For now, maybe you should at least crack a window while you’re printing.

Remember Duracell’s PowerCheck? The idea was that a strip built into the battery would show if the battery was good or not. Sure, you could always get a meter or a dedicated battery tester — but PowerCheck put the tester right in the battery. [Technology Connections] has an interesting video on how these worked and why you don’t see them today. You can see it below.

Duracell didn’t invent the technology. The patent belonged to Kodak, and there were some patent issues, too, but the ones on the Duracell batteries used the Kodak system. In practice, you pushed two dots on the battery, and you could see a color strip that showed how much capacity the battery had left. It did this by measuring the voltage and assuming that the cell’s voltage would track its health. It also assumed — as is clearly printed on the battery — that you were testing at 70 degrees F.

The temperature was important because the secret to the PowerCheck is a liquid crystal that turns color as it gets hot. When you press the dots, the label connects a little resistor, causing the crystals to get warm. The video shows the label taken apart so you can see what’s inside of it. The resistor isn’t linear so that’s how it changes only part of the bar to change color when the battery is weak but not dead.

It is a genius design that is simple enough to print on a label for an extremely low cost and has virtually no components. PowerCheck vanished from batteries almost as suddenly as it appeared. Some of it was due to patent disputes. But the video purports that normal people don’t really test batteries.

Watch out for old batteries in gear. Of course, if you want to really test batteries, you are going to need more equipment.