Feedback on Cellulose

Feedback on Cellulose

I enjoyed your article on cellulose insulation in the September/October ‘93 issue of EBN. In general, I thought the article was very well done, but felt that your recommendations on the health concerns left a bit to be desired. First of all, your recommendation not to eat it is obvious, yet by stating it, you seem to trivialize the subject. Your second point is very good—wear proper respiratory protection. After all, it isn’t good to breathe any kind of dust. This is especially important for workers who dump bags of insulation into the hopper, and those who work in closed spaces like attics. I would add that a good quality cartridge respirator is much more effective than a disposable nuisance mask.

Your third point is also good—install it behind a continuous air-tight barrier. Even under the best of circumstances, when conscientious well-trained workers are blowing cellulose into wall cavities, it is possible to have some insulation infiltrate into the living space. Small amounts often enter around loose-fitting moldings or missing electrical plates. This is easy to block by doing some interior caulking and replacing cover plates. A more serious point of entry involves the fact that many houses utilize building cavities for HVAC ducts. For example, return air often flows in joist and stud spaces. When these spaces get insulation in them, and they often do, cellulose can easily be pulled into the air handler and distributed throughout the house.

There are a number of instances where individuals have become seriously ill after their house was insulated with cellulose insulation. I know of one case where a return duct in a building cavity was filled with insulation. The furnace fan blew the insulation throughout the house. The owner developed Multiple Chemical Sensitivities, the pet dog had convulsions, tropical fish died, and house plants wilted. Granted, this is an anecdotal story, not hard scientific evidence, but there are other cases as well. The elderly, infants, and the sick are the most likely to be affected.

Cellulose insulation isn’t non-toxic. You shouldn’t eat it, and you shouldn’t breathe it. On the other hand, I believe that if installers monitor the interior of the house and check to make sure that it doesn’t get into the duct system, cellulose can be installed safely. I know many good installers who I would trust to insulate my house in a heathy manner. Unfortunately, we live in an imperfect world and there are workers who simply don’t have the training to know when they are creating a problem, or what the health consequences might be. While it might be unlikely that a cellulose insulation job will make the occupants ill, it does occasionally happen and installers need to know that it is possible.

Finally, regarding the article discussing the health implications of cellulose insulation that appeared in the

British Journal of Industrial Medicine, it is always helpful to consider the source. Some industry-sponsored research is obviously biased, but some does contain information based on good science that can be useful. After all, it was research sponsored by Velsicol Chemical Co. that helped get their own product Chlordane off the market.

John Bower

The Healthy House Institute

Unionville, IN

Congratulations on an obviously very well researched and written article on cellulose. I am hard pressed to object to much you wrote but I do have a few comments.

First, health research. No medical research has been done on cellulose, even though the heavy concentration of some rather toxic chemicals should raise some concern. The Insulation Contractors Association of America (ICAA) has formally written to CIMA concerning this issue and has received no replies.

Related to this is the issue of protective gear. Your Point 4 on page 17 recommends “adequate” respiratory protection. I believe the fine dust from blown cellulose is too fine to be properly screened by the masks used for

fiberglass.

On page 13, you talk of weight. I think that if you blow over an R-26 layer of cellulose in an attic, heavier ceiling board must be used. I do not think the industry warns builders and homeowners of this issue.

Next, the University of Colorado testing you referred to on page 13. This research, often cited by the cellulose industry, was conducted without wallboard on the walls. Data came from a preliminary report. When the first report was given at the 1990 EEBA Conference, they dropped reference to air leakage. Perhaps they recognized that blower door tests on incomplete structures are highly questionable. NAIMA is now finishing some very good research at Holometrix on air infiltration.

Finally, fire safety. I agree with you; this is the most significant concern relating to cellulose. From my recent involvement with the fire fighting community, I am convinced the number of fires involving cellulose is far understated. Would you be interested in research among fire fighters that shows a much higher incidence of cellulose attic fires?

Thomas A. Newton

CertainTeed Corporation

Valley Forge, PA