I think the issue that is under discussion is directed towards ensuring that the best possible quality of data is used for risk assessments and advisories. Risk management responses need to use the best quality data that can be obtained, and guard against inclusion of poor quality data that dilute understanding rather than contribute to it. This is true in all areas of research, but in responses to environmental risks there have occasionally been violations of the precautionary principle as the result of well intentioned, but poorly informed individuals that are rushing to push forward the precautionary principle. The EPA’s strategic plan for evaluating the toxicity in chemicals that was released in March of this year (http://www.epa.gov/osa/spc/toxicitytesting/) addresses some of the issues that Monona raises, and it describes an insightful emphasis on ensuring that its core assumptions and policies are well grounded in science.

I recall hearing a lecture by Bruce Ames or one of his colleagues that pointed out that the Ames test for assessing carcinogenicity was being grossly misused. Apparently, the test was being applied to obtain quick and relatively cheap results, but not necessarily results that meant what everyone assumed. As a result, a number of test results were of questionable validity, possibly inaccurately excusing some serious carcinogens, but also mistakenly indicating carcinogenic risks where none actually existed.

In the discussion that followed that presentation, there was also mention that any physiological insult that increases cell death and induces rapid replacement of cells in exposed animal tissues can result in an increased cancer incidence in test animals. As I recall from that discussion, carcinogenesis in some animal studies had occurred because of increased cell turnover to replace the damaged tissues, not because of molecular damage to DNA. It sounded as though anytime cell turnover was increased, (even if it was induced by high sucrose, high sodium chloride, high … exposures) it would be accompanied by increased cancer incidence that was similar to those that accompanied similar levels of cytotoxicity induced by exposure to “carcinogenic” chemicals (e.g., sodium cyclamate). Initiation of cancer through such non-specific mechanisms would not appear to be applicable to low level exposures to these same agents. This is clearly distinct from carcinogenic chemicals where direct molecular mechanisms have been recognized.

I would like to hear from group members whether the observations mentioned at that lecture above have been verified or disproven by recent studies. Carcinogenesis is outside of my area of interest since I study the molecular mechanisms of toxic trace elements. But trace element toxicity has experienced a number of controversies because many toxicologists have had an incomplete understanding of basic physiology. If similar misunderstandings of carcinogenicity evaluation, approaches, and data quality are occurring, it seems this points towards a systemic problem in risk assessment, possibly because so many researchers in these areas of study are tasked with doing so much with so little funding. To rephrase Winston Churchill; the public expects so much, for so little, from so few.

Thanks,

Nick

Nicholas V.C. Ralston, Ph.D.

Health Effects Research Program Leader
Energy & Environmental Research Center
University of North Dakota
15 North 23rd Street
Grand Forks, ND 58202-9018
Office 701-777-5066
Lab 701-777-5392
FAX  701-777-5181
Cell    218-791-2838

The key weakness of science is our incomplete understanding of the system of systems that comprise each system.

Read over the 280+ pages of the IARC monograph and look at all of the data gathered not only from the plywood industry studies but many other industries.  Look at the whole picture and you will see why they found sufficient evidence that formaldehyde causes nasopharyngeal cancer, a rare cancer in humans, limited evidence for cancer of nasal cavity and sinuses, strong but not sufficient evidence for leukemia, and other evidence.  As a result, they have determined that formaldehyde belongs in Group 1, defined as "carcinogenic to humans."

What is this discussion really about?  Why wouldn't every chemist, safety professional, and college teacher want workers and students to know that formaldehyde and/or paraformaldehyde could be hazardous to their health?  What  motivates a safety professional or teacher to discount or diminish potential hazards?  Does anyone think that college students are so unable to deal with risk that knowing paraformaldehyde might be a carcinogen would send them screaming into the streets?  Hell, they think they are immortal.

I personally think we should warn lab workers and students not only about chemicals that are actually listed by IARC, NTP or OSHA, but require them to take precautions with all of the chemicals they use because most of them have never been evaluated for cancer and other toxic effects. This is why the EU REACH program required testing of about 29,000 chemicals high production volume chemicals.  

Every lab worker and student should know that only about 900 chemicals have been evaluated for cancer effects.  Yet CAS recently registered it's 50 millionth chemical. The last 10 million of these chemicals were registered in 9 months at the rate of 25 chemicals per minute.  The primary sources for these new chemicals were patents and chemical catalogs indicating some are already in use.  They are out there with no cancer testing at all, since cancer tests take two years. 

Even fewer chemicals have been studied for reproductive, developmental, neurological, and other organ system damage on a chronic basis.  There is a vast amount we don't know about chemicals.  That's why diacetyl, a chemical isolated from butter, is now found responsible for a fatal lung disease when inhaled.  And why titanium dioxide thought to be a completely safe substitute for lead white in paints is now listed as an IARC lung carcinogen.  And so on, and on, and on.

But there is a simple answer to all of this in the lab, and that is: "no one was ever harmed by a chemical to which they were not exposed!"  So do the process in the hood and put on the gloves, goggles, and any other protective equipment required. No exposure?  No hazard.

Whew.   Thanks.   I feel a lot better now.  Monona Rossol

    As an aside, if formaldehyde WERE a nasal carcinogen Washington and Oregon as leading producers of plywood , made using formaldehyde adhesives, should have extraordinary numbers of nasal cancers in their cancer registries. I do not think that is the case. In any analysis one would also have to consider wood dust as a potential carcinogen. Damm, life does get complicated when you have to consider all the facts!!
   
   Best regards,
      Roger
--
Advisor, Toxicology and Human Health Risk Analysis
13701 Quaking Aspen Place NE
Albuquerque, NM 87111
Tel: 505-296-7083
Fax: 505-296-9573
E-mail: roger.o.mcclellan**At_Symbol_Here**att.net