Is working next to a printer as bad as inhaling secondhand smoke? A study by researchers at Queensland University of Technology's Air Quality and Health Program says that might be the case.
The Australian research team tested 62 recent laser-printer models from Canon, HP LaserJet, Ricoh and Toshiba in order to measure the levels of emissions they produced. Researchers tested the printers in an open-plan office, the sort of floor plan found in many offices around the world, and in a controlled chamber.
The tests showed that some printers emitted tiny bits of toner in the form of ultrafine particles (UFPs). These particles can penetrate into the lungs and, the study's authors say, lead to respiratory complications, cardiovascular problems and cancer. Dr. Lidia Morawska, the study's lead researcher, and her coauthors compared the health effects to those from cigarettes. The researchers fear that these UFPs may contain carcinogens [Source: ZDNet].
Printers were assigned to categories based on level of UFP emissions: non-emitter (37), low-level emitter (six), medium-level emitter (two) or high-level emitter (17). Twelve of the high-level emitters were HP printers. Though they're similar in design, photocopiers produced no emissions.
In the open-plan office test, airborne particles increased 500 percent during the workday [Source: BBC News]. Researchers also found that emissions levels were elevated even when printers were on standby. New cartridges and print jobs requiring lots of ink (such as images) produced more emissions.
Soon after Dr. Morawska and her team published their study in Environmental Science & Technology, a publication of the American Chemical Society, HP released an official statement, criticizing the study and its claims. HP said that they "do not believe there is a link between printer emissions and any public health risk" [Source: HP]. They did acknowledge that "ultrafine, fine and coarse particles are emitted from printing systems" but said they were "below recognized occupational exposure limits" [Source: HP]. The company also said that it performs rigorous testing and adheres to guidelines from more than one environmental organization.
Before we look at what others are saying about the study, let's take a closer look at what the researchers were concerned about: ultrafine particles and printer toner. UFPs are tiny particles, less than 0.1 micrometer in size -- or 1/1000th the size of a normal dust particle. The EPA and other organizations are performing research on UFPs, some of it related to concerns about possible health effects from nanotechnology. The small size of UFPs allows them to penetrate into human alveoli, the sacs inside our lungs. Once inside, their ability to do harm depends on their chemical composition. That's where printer toner comes in.
Toner is the ink used by laser printers. It's different from the ink found in inkjet printers. Laser toner is made up of a dry, ultrafine powder, which has a positive electrical charge so that it sticks to the printer's drum. Laser toner also contains a compound called carbon black, which the International Agency for Research on Cancer (IARC) calls a Class 2B carcinogen [Source: IARC]. By the IARC's standards, that means that carbon black is "possibly" carcinogenic to humans. The IARC tests show that "sufficient evidence" exists to show that carbon black is carcinogenic to animals, while "inadequate evidence" exists to prove that it's carcinogenic to humans [Source: IARC].
So if carbon black is possibly carcinogenic to humans and is found in laser toner, does that mean that it's in UFPs produced by laser printers? And, in turn, should we be worried about the health effects of those UFPs? On the next page, we'll look at what we know and don't know about laser-printer emissions.
Why Not to Fear Laser Printers -- Yet
The study performed at Queensland University of Technology compares the possible health effects of laser-printer use to those of cigarettes, but as many experts point out, much information remains unknown. First, the composition of these UFPs is not fully understood. Critics and experts alike who have commented on the study, including the researchers themselves, agree that more research is needed about the effects of UFPs. Scientists must better understand what UFPs are, their health consequences and how and if they should be monitored and managed.
Some scientists, including several at the Lawrence Berkeley National Laboratory, say no clear link exists between ultrafine particles from printers and negative health effects. They, too, call for more research about these particles and how printer characteristics, like cartridge type or the age of a printer, affect emissions.
Besides the lack of knowledge about UFPs, the study might be made weaker by the types of printers used. Most of the printers were manufactured by HP, although that company sells more printers than any other company in the world. But Dr. Morawska's team didn't test printers from some other large manufacturers, including Epson, Lexmark and Brother.
The study provides information about the quantity of UFP emissions, but it doesn't tell us what's in the emissions. These emissions may come from toner, but what's in them? It may be harmful carcinogens and toner compounds, but HP claims they could also be condensation produced by the printing process and points out that other appliances, like toasters, produce UFPs. Additionally, the conclusion appears to compare UFP emissions to secondhand smoke based on the quantity of the particles -- not because of the actual toxicity of the emissions.
Robert Hamers of the University of Wisconsin's chemistry department told the Associated Press that laser-printer UFPs are "probably much less toxic than cigarette smoke," though he didn't cite any research [Source: Washington Post]. Another chemist called it a "preliminary finding" and not a reason to alter one's routine [Source: Washington Post].
In countering these criticisms, Dr. Morawska said that the most recent World Health Organization Air Quality Guidelines mention the ill health effects of ultrafine particles [Source: Sydney Morning Herald]. Though she acknowledged more research is needed, Dr. Morawska said that governments need to regulate printer emissions, offices should put printers in areas with good ventilation and manufacturers should work to reduce emissions.
Whether laser-printer UFPs will lead to printers being labeled as dangerous as cigarettes remains uncertain. But the research out of Australia has started a conversation about the subject that will surely lead to more studies in the future. For now, you're likely not risking your life by using a laser printer, but it can't hurt to keep your printer in an open, well-ventilated area.
For more information about laser printers, UFPs and related topics, please check out the links on the next page.
Related HowStuffWorks Articles
More Great Links
- "Carbon Black." International Agency for Research on Cancer. http://monographs.iarc.fr/ENG/Meetings/93-carbonblack.pdf
- "Glossary: Fine particles, ultrafine particles." Green Facts. Oct. 25, 2006. http://www.greenfacts.org/glossary/def/fine-particles-ultrafine-particles.htm
- "Light Corporation glossary of lighting terms." Light Corporation. http://www.lightcorp.com/glossary.cfm
- "Printer Emissions Report from Queensland University of Technology." HP. Aug. 2, 2007. http://www.hp.com/hpinfo/newsroom/emissions.html
- "Study: Laser printers may pose health risks." ZDNet News. Aug. 1, 2007. http://news.zdnet.com/2100-9584_22-6200085.html
- "What is toner?" Webopedia Computer Dictionary. http://www.webopedia.com/TERM/T/toner.html
- Berlind, David. "HP on potentially dangerous laser printer emissions: Our printers no riskier than toasters." ZDNet. Aug. 3, 2007. http://blogs.zdnet.com/BTL/?p=5855
- Bryant, Nick. "Office printers 'are health risk.'" BBC News. July 31, 2007. http://news.bbc.co.uk/2/hi/asia-pacific/6923915.stm
- He, Congrong, Morawska, Lidia and Taplin, Len. "Particle Emission Characteristics of Office Printers." Queensland University of Technology. July 10, 2007. http://cdn.sfgate.com/chronicle/acrobat/2007/08/01/printer_es063049z.pdf
- Judge, Peter and Meyer, David. "Printer Emissions as Bad as Cigarettes?" BusinessWeek. Aug. 2, 2007. http://www.businessweek.com/globalbiz/content/aug2007/gb2007082_765131.htm?chan=globalbiz_europe+index+page_top+stories
- Keizer, Gregg. "HP Dismisses Laser Printer Health Risks." Computerworld. PC World. Aug. 3, 2007. http://www.pcworld.com/article/id,135496-c,monochromelaser/article.html
- Moses, Asher. "Printer makers reject health risk claim." The Sydney Morning Herald. Aug. 6, 2007. http://www.smh.com.au/news/home-office/printer-makers-reject-health-risk-claim/2007/08/06/1186252606707.html
- Ramde, Dinesh. "Printers Found to Kick Up Particles." The Associated Press. The Washington Post. Aug. 3, 2007. http://www.washingtonpost.com/wp-dyn/content/article/2007/08/03/AR2007080301692.html