The controversy concerning the soybean processing plant in Conoy Township has captured various interest groups as one would expect. There are concerns and attempts to address concerns which are also expected. Hopefully the construction and opening of the plant will be accomplished with the goal based on best available science to minimize and prevent ground water and air contamination and to protect the health of residents within the immediate surroundings as well as those who live east of prevailing winds. It is great that everyone is being proactive as any adverse environmental and/or health outcome will be a negative for those who operate the plant as well as those residents who are potentially impacted.
Hexane is one of many solvents or volatile organic compounds (VOC) used in industry. Hexane is included in the list of chemicals on the US Toxic Release Inventory and regulations on the release of hexane gas have been issued due to potential carcinogenic properties and environmental concerns. The plant operators are aware of these various regulations, and based on the level of experience in utilizing hexane in similar soybean processing facilities, should be readily able to meet these standards.
Emitted hexane will also be important in regard to total VOC emissions as applicable to air pollution and ozone generation. Even if the plant meets current EPA standards for hexane emissions, how will the hexane emissions contribute to total VOC emissions when including other potential VOC release sources within the area? Being reassured that any additional hexane emissions will not impact total VOC emissions and, therefore, air quality standards as applicable to ozone would be encouraging.
Hexane is a fat soluble solvent and long-term toxicity studies at 400 to 600 ppm exposure levels have been associated with peripheral neuropathy (loss of tactile, temperature and position sense) as well as central nervous system disorders. The EPA set emission standards in regard to a specific chemical and corresponding health effects. These standards, however, do not take into consideration combined chemical entities which have similar toxicities. What will be the potential long term health impact as a result of cumulative exposure to hexane plus VOC released from other sources? An answer to this question is not currently available based on the current scientific literature. As a precautionary public health principle, however, until better science is available, every effort should be made to maintain and continuously improve control measures to lower environmental release of VOC including hexane into the surrounding community.
We need to know what other solvents to process soybeans and their potential health effects. Total ambient air of VOC emitted in the township is needed. Are VOC including hexane released from the plant, either from this plant alone or in combination with surrounding industries, a potential long-term health hazard?
Hexane can be substituted in soybean processing by isohexane which the industry recognizes as safer in regards to potential toxicological effects. Will this derivative be used in the production process?
We all should be vigilant and not rest on the emission standards by the EPA which do not address long-term toxicity in humans from exposure to total VOC emitted into our environment. If there are no answers, perhaps management of the soybean processing plant can help reassure the local community through town hall meetings, web site postings, and through formation of a joint local industry/community advisory group that they are taking an on going precautionary public health approach and will strive to continuously improve environmental controls technology to lower the release of VOC’s into the surrounding community.
Stephen D. Lockey, III, M.D.