HP on potentially dangerous laser printer emissions: Our printers no riskier than toasters

In yesterday's blog post about the potentially dangerous laser printer emissions that were uncovered by Queensland University of Technology in Australia, I noted that HP's LaserJets bore the brunt of the study's findings and that I'd follow up when HP delivered the response it promised. That response showed up in my e-mail late last night.

Citing inadequate scientific techniques for particle analysis as well as HP's performance within certain international standards and guidelines, the company is disputing the claims of the Australian researchers. Those researchers discovered the problem by chance when "an investigation of office ventilation systems, carried out jointly between the university and the Queensland Department of Public Works, found five times as many particles indoors as those produced by traffic outdoors. Using an electronic sniffer, researchers traced the emissions to printers." As can be seen from the response below, HP notes that even the emissions from toasters cannot be "accurately characterized," thus drawing into question any conclusion that the emissions from laser printers could pose health risks.

Meanwhile, since posting that first blog, I've heard from several people including ZDNet's own Marc Wagner that toner particles have been known to be carcinogenic for a long time. I did some searching on my own and while you'll see a lot of references to toner particles being carcinogenic in the search results, I was unable to find any specific citations of the problem at the various carcinogen-tracking agencies like the IARC. What I was able to determine however, is that carbon black, a material know to be used in laser printer toner, is classified by the IARC as a Class 2B carcinogen. Where as Class 1 is definitely carcinogenic and Class 2B is "probably" carcinogenic, 2B is "possibly" carcinogenic to humans. One document I found said:

The IARC evaluated carbon black, as a Group 2B carcinogen, for which there is inadequate human evidence, but sufficient animal evidence. The latter is based upon the development of lung tumors in rats receiving chronic inhalation exposure to powdered carbon black at levels that induce particle overload of the lung. However, there is a two-year inhalation study of a toner containing carbon black which demonstrated no association between toner exposure and tumor development in rats.

Even if carbon black were a probable carcinogen, connecting that dot to the particle emission study done in Australia is connection that can't be made yet. Rather than focusing on the chemical composition of emitted particles, the study focuses on their concentration and volume (a technique that is also used to rate the effects of second hand smoke). At the very least, the study raises the question of whether the tested printers produce concentrations that are unhealthy, regardless of particle type.

So, to the extent that HP is saying "you can't say our printers cause cancer because the particles in question haven't been accurately characterized to be carcinogenic," that appears to be true. Are the particles toner particles? Do they have carbon black or some other IARC-rated carcinogen in them? These questions remain unanswered. On the issue of particle concentration, HP seems to be arguing that its printers meet all accepted standards in terms of particle emission (regardless of particle type).

Here is the full response from Tuan Tran, HP's vice president of marketing for supplies:

After a preliminary review of the Queensland University of Technology research on particle emission characteristics of office printers, HP does not agree with its conclusion or some of the bold claims the authors have made recently in press reports.

HP stands behind the safety of its products. Testing of ultrafine particles is a very new scientific discipline. There are no indications that ultrafine particle (UFP) emissions from laser printing systems are associated with special health risks. Currently, the nature and chemical composition of such particles whether from a laser printer or from a toaster cannot be accurately characterized by analytical technology. However, many experts believe that many of the UFPs found in common household and office products are not discrete solid particles, but may be condensation products or small droplets created during thermal processes.

HP agrees more testing in this area is needed, which is why we've been active with two of the world's leading independent authorities on this subject: Air Quality Sciences in the United States and the Wilhelm-Klauditz Institute in Germany.

Vigorous tests are an integral part of HP's research and development and its strict quality-control procedures. HP LaserJet printing systems, original HP print cartridges and papers are tested for dust release and possible material emissions and are compliant with all applicable international health and safety requirements. In addition to meeting or exceeding these guidelines, HP's design criteria for its laser printing systems incorporate guidelines from both the Blue Angel program in Germany and the Greenguard program in the United States.

Based on our own testing, HP knows that many variables can affect the outcome of tests for ultrafine particle emissions. Although HP is not aware of all of the specific methodologies used in the Queensland study, based on what we've seen in the report as well as our own work in this area, we do not believe there is a link between printer emissions and any public health risk. Specifically, HP does not see an association between printer use by customers and negative health effects for volatile organic compounds, ozone or dust. While we recognize ultrafine, fine, and coarse particles are emitted from printing systems, these levels are consistently below recognized occupational exposure limits.

HP hopes to learn more from the study authors about how products were chosen for the study, how ranges were determined given no standards exist, and many other factors that could have influenced the results.

Bottom line? Fair questions remain. Do the ultra fine particles (UFPs) floating in the air around laser printers contain toner and if so, do they have carbon black or some other carcinogen in their composition (potentially rendering the concentration question moot)? Irregardless of the standards to which the laser printers conform (HP's as well as those of other manufacturers), are those standards up to par with the most recent findings when it comes to the health effects of UFPs and/or inert dust in certain concentrations?

One thing is for sure. As long as the jury is still out (and judging by HP's saying that more testing needs to be done, it is clearly out), I'm glad I don't have a laser printer in the house. Especially near my kids.