Clay Times Back Issues Vol. 21 Issue 99 - Winter/Spring 2015 - Page 30

Studio I Health & Safety CLAYTIMES·COM n WINTER / SPRING 2015 All About Wax, cont. gasoline, coal, wood, or cigarettes, the issues are basically the same. For example, cigarette smoke is not toxic due to nicotine, which is a mild yet highly addictive drug. It is the emissions from the burning [tobacco] leaf that kill. While there are hundreds or thousands of toxic chemicals emitted by hot or burning wax, they have not been well studied except in wax candle emissions. Candle Studies Many candle sellers’ Websites state clearly that no studies have shown candles to be an indoor air quality hazard. Since this statement has been used by candle sellers for over 10 years, I looked for a source they must be using to support this. I found that it is likely to be from an EPA Report called “Candles and Incense as Potential Sources of Indoor Air Pollution: Market Analysis and Literature Review,” dated January, 2001. This is a review of all of the studies that were available in 2001. The EPA summarizes data from air tests from all the studies and compared the amounts of various chemicals emitted by burning candles: acetaldehyde, formaldehyde, acrolein, polyaromatic hydrocarbons (PAHs), benzo[a]pyrene, and naphthalene. These are all toxic chemicals commonly found in the burning of almost any hydrocarbon from wax, to gasoline, to coal, wood, and cigarettes. The sentence that the candlemakers seem to quote comes from the first sentence in a paragraph in their Conclusion. This sentence reads: “The European Candle Association (1997) and Schwind and Hosseinpour (1994) conclude that there is no health hazard associated with candle burning, even when a worstcase scenario of 30 candles burning for 4 hours in a 50 m 3 [cubic meter] room is assumed.” So EPA is saying that an alliance of the biggest candle manufacturers in the EU, called the European Candle Association, and the authors of a study done at their behest, say there is no hazard. But in the very next sentence EPA says that they interpret this data differently: “... However, burning several candles exceeded the EPA’s 10 6 increased risk for cancer for acetaldehyde and formaldehyde, and exceeded the RfC* for acrolein.” * The 10 6 (1 cancer in a million people) is the level at which the cancer risk is not acceptable for air quality. The RfC is the constant exposure level that is harmful for people in ways other than cancer. In other words, there is a measurable cancer and respiratory risk from the level of the acetaldehyde, formaldehyde, and acrolein found in these studies. Further in the conclusion, EPA notes that there is no data on candle soot, which is a known hazard, and a number of other cancer-causing chemicals also known to exist in candle emissions. These substances add to the toxicity of candle emissions. While the actual risk from burning candles cannot be assessed without a lot more data, the studies do make one thing clear: burning candles or any other substance indoors will not do your air quality, or you, any good. It is the same with wax in the studio or the kiln room. How to Protect Yourself 1. Use cold wax emulsions instead of hot wax. These really should be the only glaze resists you use. There is no reason to set up expensive ventilation for melting wax when the use of cold wax, readily available from most ceramic suppliers, avoids the problem. 2. Vent the kiln and the kiln room. The best ventilation systems for electric kilns are the negative pressure systems that draw a small amount of air from the bottom of the kiln. However, these systems will not work well if you use a lot of wax resist. The burning wax creates a large volume of gases and vapors whose pressure can overpower the small amount of negative pressure in the kiln system. So it is important to also have an exhaust fan and air supply system in your kiln room to exchange the air during the low temperature part of the firing in which organic matter like wax is burned off. 3. Gas kilns need both a stack for exhausting the combustion gases, AND a secondary exhaust for any escaping emissions or reduction. The Bailey gas kiln ventilation system with combustion, spy, burner port and residual collection hoods (on the Deluxe and Production series kilns) is a fine example of this kind of ventilation. How to Get the Data Sheet If you want a copy of this data sheet, send an e-mail with your postal address to actsnyc@cs.com and I’ll put one in the mail. [ Footnotes: 1. Two Federal Register documents: 78 FR 65242-654244, October 31, 2013 and 78 FR 56274-56504, September 12, 2013. 2. Clay Times, July/Aug 2005 and Nov/Dec 2005. Monona Rossol is an industrial hygienist/chemist with an M.F.A. in ceramics/glass. E-mail her at: ACTSNYC@cs.com 30 Studio I Health & Safety All About Wax, cont. gasoline, coal, wood, or cigarettes, the issues are basically the same. For example, cigarette smoke is not toxic due to nicotine, which is a mild yet highly addictive drug. It is the emissions from the burning [tobacco] leaf that kill. While there are hundreds or thousands of toxic chemicals emitted by hot or burning wax, they have not been well studied except in wax candle emissions. Candle Studies Many candle sellers’ Websites state clearly that no studies have shown candles to be an indoor air quality hazard. 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