Effective July 29, 2011 the California Office of Environmental Health Hazard Assessment (OEHHA) added sulfur dioxide (CAS. No. 7446-090-05) to the Proposition 65 list of chemicals known to the state to cause reproductive toxicity. Sulfur dioxide is found in numerous products including food and beverages.
Proposition 65 is the statute that requires notification by manufacturers of consumer goods and employers of potential exposure to chemicals which are on a list of chemicals “known” to the State of California to cause cancer or reproductive effects on such products or workplaces must be properly labeled or have proper signage.
Sulfur dioxide (SO2) is a colorless, nonflammable gas with a pungent odor. As a component of ambient air pollution, SO2 is found in combination with sulfuric acid, sulfur trioxide, ozone, nitrogen dioxide, and particulates, and its presence in ambient air occurs primarily as a result of fossil fuel consumption at power generation and other industrial facilities.
Considered through the Developmental and Reproductive Toxicant Identification Committee (DARTIC) in its official capacity as the “state’s qualified experts” at a public meeting held on July 12 and 13, 2011, the DARTIC determined that sulfur dioxide was clearly shown, through scientifically valid testing to cause developmental toxicity, an endpoint of reproductive toxicity. The DARTIC did not find that sulfur dioxide has been clearly shown to cause female or male reproductive toxicity. Comments were submitted by Cambridge Environmental analyzing the lact of data to support the decsion.
SO2 uses are myriad. SO2 has pesticidal uses and was ranked 82nd out of the top 100 pesticides used statewide in California in 2007. In 2008, 187,535 pounds of SO2 were reported as having been used in California. Specific uses include sanitizing equipment for wine production and storage, and post-harvest commodity fumigation of fruit including grapes. Because of its use in preservatives and pesticides it is frequently found in fruit and related products.
While inhalation is repeatedly the most significant route of exposure, dermal and oral exposures are also possible. Endogenous or added sulfites, which release SO2, can be consumed in food or drink. Sulfites are also found in some cosmetic and personal care products, raising the potential for dermal as well as aerosol exposures from the use of these products.
Sulfites can also be produced as a result of fermentation in some foods and beverages, such as beer and wine. The U.S. Food and Drug Administration (FDA) has estimated average per capita SO2 consumption at about 0.2 mg/kg-day, with estimates of up to 2 mg/kg-day for individuals consuming foods and beverages relatively high in SO2 content. Note, however that The Prop 65 MADL does not apply to sulfites, bisulfites or metanisulfites. These chemicals are not currently listed under Proposition 65 and exposure to them, at any level, is not subject to the warning requirements of Proposition 65.
With certain restrictions, sulfiting agents are approved for use as sanitizing agents, inhibitors of undesirable microbial growth, and to prevent oxidative browning of foods. Residual sulfites in treated foods usually do not exceed several hundred parts per million (ppm), but may approach 1,000 ppm (i.e., 0.1%) in some products.
Exposure to SO2 in California also results from the combustion of sulfur-containing fuel by mobile sources, and from several industrial processes, such as petroleum refining, the smelting of sulfide ores, the manufacture of hydrosulfites. More specifically, in the bleaching of wood pulp and paper and food bleaching and processing. Pesticidal and sterilant applications, waste and water treatment, the use of SO2 in manufacturing, as well as volcanic emissions and other natural sources can also result in SO2. Because SO2 is found in numerous consumer products it may open yet another avenue for challenges; these may be complicated by the fact that the defense the SO2 was naturally ocurring would be difficult.
We will have to see what the eventual fallout of this listing is as SO2 is found in numerous consumer products and it may open yet another avenue for multiple product suits. Further unlike some other food contaminants challenges; the defense that SO2 is naturally occurring will be difficult. Additionally another section of Propostion 65 prohibits the discharge of Prop 65 into water bodies, this may create issues for anyone using it to treat waste water that then discharges into a water body.