What's This All About?
Many owners of ceramic charcoal cookers have replaced factory gaskets with various replacement gasket materials when the original gaskets fail. However, there have been concerns raised about the safety of using Rutland Grapho-Glas gasket kits on ceramic charcoal cookers. (There have also been concerns raised about ceramic gaskets, but this document only addresses the Rutland Grapho-Glas product.) Where did all the concern come from? Posters on ceramic charcoal cooker bulletin boards have posted that they were told, either by Rutland or by the manufacturer of their cooker, that the Rutland gasket is not safe for use around food. Some claim to have been told that Rutland has stated that using their product around food can result in harm to unborn fetuses. As result, there have been numerous arguments, sometimes heated, on these bulletin boards about the safety of using Rutland gasket material on ceramic charcoal cookers. We will do our best to provide you with the information we have been able to accumulate on the subject so you can make an informed decision as to whether or not you wish to use this product on your ceramic charcoal cooker.
What would any document about health and safety be without a disclaimer? Well, here's ours. We don't claim to know if it is safe for you to use a Rutland gasket product on your ceramic cooker. Any opinions stated here are just that, opinions. It is up to you to evaluate the information presented here and make your own decision as to whether or not you wish to use Rutland gasket material on your cooker.
The Letter From Rutland
In order to try to better understand what might be the source of some of these claims, and to get an actual statement from the Rutland Fire Clay Company regarding the use of their product on a ceramic charcoal cooker, we contacted Rutland and asked for a letter stating their position. We informed Rutland that the letter would be published on our website and we did receive permission to do so. Here's the letter:
We'll summarize the main points of this letter, points that are important to understanding what was actually stated by Rutland:
Where does this leave us? Since Rutland's letter didn't contain any information regarding the safety of using their product around food, we can look to some other sources of information. First of all, Rutland has published a Material Safety Data Sheet (MSDS) and a Technical Data Sheet for their product. Also, their product is made from fiberglass and graphite. There are MSDSs published for these two materials that can be examined for information about the safety of using these materials. So let's look:
The first thing you should notice is that the Rutland MSDS indicates a Hazardous Materials Identification System (HMIS) rating of 1 for health. This indicates that any health risks listed are "slight." The health hazards listed are:
Inhalation: Acute: mechanical irritation of the mouth, nose and throat. Chronic: none known.So the only hazards listed on Rutland's own MSDS are simply mechanical irritation of any affected area. No chronic hazards are known to them. What about Rutland's Technical Data Sheet? It merely says "Not recommended to come in contact with food." Since food isn't going to come into contact with a gasket on a ceramic charcoal cooker, we can only conclude based upon Rutland's own data sheets that there are no significant health hazards associated with Grapho-Glas gaskets known to Rutland.
Skin: Acute: minor irritation. Chronic: none known.
Eye Contact: Acute: direct contact will cause mechanical irritation. Chronic: none known.
Ingestion: unlikely to occur.
We found an MSDS for fiberglass published by Owens-Corning, certainly one of the biggest names in fiberglass. Here's what they have to say about potential health effects of fiberglass:
ACUTE (short term): Fiber glass continuous filament is a mechanical irritant. Breathing dusts and fibers may cause short term irritation of the mouth, nose and throat. Skin contact with dust and fibers may cause itching and short term irritation. Eye contact with dust and fibers may cause short term mechanical irritation. Ingestion may cause short term mechanical irritation of the stomach and intestines. See Section 8 for exposure controls.Further, we find the following information regarding any carcinogenic effects of fiberglass:
CHRONIC (long term): There is (sic) no known health effects connected with long term use or contact with this product. See Section 11 of MSDS for more toxicological data.
The International Agency for Research on Cancer (IARC) in June, 1987, categorized fiber glass continuous filament as not classifiable with respect to human carcinogenicity (Group 3). The evidence from human as well as animal studies was evaluated by IARC as insufficient to classify fiber glass continuous filament as a possible, probable, or confirmed cancer causing material.So, we find no reason to think that fiberglass is a hazardous material to be using for a gasket on a ceramic charcoal cooker.
We know, however, that the Rutland Grapho-Glas gasket material also contains graphite. So we found some MSDSs for graphite.
Graphteck: Indicates that "Prolonged and repeated overexposure may lead to benign pneumoconiosis." Otherwise, it lists no health hazards.So, here we do find references to several serious health conditions. What should we make of that? Well, the health hazards are listed as "slight" in the Hazardous Materials Identification System. Also, the serious conditions are listed as being associated with prolonged and constant exposure.
Fisher Scientific: Lists eye irritation or conjunctivitis, skin irritation, intestinal irritation if you ingest large quantities, respiratory irritation, and potential silicosis caused by prolonged inhalation/exposure. It also states that it contains trace amounts of quartz which may also lead to cancer.
West System: Lists respiratory tract irritation with short term inhalation, mild skin irritation to short term exposure and moderate irritation from eye contact. It also lists symptoms of overexposure as respiratory irritation, shortness of breath or coughing, red, irritated skin and eye irritation. Finally it states that prolonged or repeated inhalation of dust may cause pulmonary fibrosis or emphysema, and is a possible lung cancer hazard. The health hazards are listed in this MSDS as having a Hazardous Materials Identification System (HMIS) rating of 1, indicating that any health risks listed are "slight."
What about the reference to cancer? OSHA says that graphite is not a cancer risk. The International Agency for Research on Cancer (IARC, an agency of the World Health Organization) lists crystalline silica (graphite contains a small amount of crystalline silica) as a Group 1 material, meaning that they consider it to be carcinogenic to humans. However, if you read the relevant IARC Monograph on the Evaluation of Carcinogenic Risks to Humans (Volume 68), you will find the following conclusion:
There is sufficient evidence in humans for the carcinogenicity of inhaled crystalline silica in the form of quartz or cristobalite from occupational sources.So again, we are talking about prolonged exposure to high levels of the substance. Many of the studies cited were of 20-30 year exposures in mine and stone cutting workers.
Inhalation versus Ingestion
Notice that all the serious health effects listed are the result of prolonged and repeated inhalation of material. There is no mention of any chronic health risks from ingestion of the material. And since the only serious health risks might result from inhalation, it should also be apparent that this material would be just as hazardous if the product were used in its intended application (wood stoves and fireplaces) as it would in a ceramic charcoal cooker. Therefore, it seems hard to justify Rutland's caution against letting food come into contact with the gasket material.
The "Danger To Unborn Fetuses" Claim
All we can say is that Rutland says they never made this claim. None of the material safety data sheets for fiberglass, graphite or the Rutland product indicate there is any danger to unborn fetuses. Frankly, we think it is totally false and perhaps originated from someone's misunderstanding of either Rutland's statements or other health risk data in the MSDSs. The bottom line is that it doesn't really matter who said what to whom. There is no data to indicate that either fiberglass or graphite will harm unborn fetuses, so any such statements are irrelevant to any decision about using Rutland gaskets on ceramic charcoal cookers.
You should carefully read all of the information available before drawing your own conclusion about the safety of using this material on your ceramic charcoal cooker. This is what we conclude:
Rutland Grapho-Glas Gasket Kit Material Safety Data Sheet (PDF)
Rutland Grapho-Glas Gasket Kit Technical Data Sheet (PDF)
Owens-Corning Fiberglass Material Safety Data Sheet (PDF)
Graphtek LLC Graphite Material Safety Data Sheet (PDF)
Fisher Scientific Graphite Material Safety Data Sheet (PDF)
West System Graphite Material Safety Data Sheet (PDF)
Hazardous Materials Identification System
IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 68, Silica, etc.
IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 81, Man-made Vitreous Fibres
Glossary of Standard IARC Clasifications