ANCHORAGE - The state plans to adopt a rule that would classify an airplane anti-icing fluid as a contaminant that could require an industrial cleanup - but only if it's accidentally dumped in bulk.
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State officials will not use the cleanup guidelines to regulate routine use of propylene glycol, a fluid with the consistency of honey, at airports. The fluid, mixed with water and sprayed from trucks, drips over runways throughout the winter.
Instead, the rules will apply to "significant" events, such as spill of several hundred gallons that leaks into soil, said Bill Janes of the Alaska Department of Environmental Conservation.
Some Anchorage aviators such as Mark "Woody" Richardson of Grant Aviation say the proposed rules are bizarre. Hundreds of thousands of gallons of the fluid, mixed with water, are sprayed on planes each winter, he said.
"What's the difference between spilling and dripping?" Richardson asked.
The Alaska Air Carriers Association, a trade group of airlines, also is reviewing the proposal, which is out for public comment this month.
Propylene glycol has enjoyed a benign reputation for decades.
The fluid is considered less harmful than ethylene glycol, which is used to melt ice and snow off aircraft. Propylene glycol also is used as an additive in cosmetics and in processed food such as ice cream and carbonated drinks, prompting disapproval from some consumer activists.
Last year, air carriers at Anchorage's international airport sprayed more than 380,000 gallons of propylene glycol and about 114,000 gallons of ethylene glycol, according to airport officials.
Most of the de-icing fluid drains to Cook Inlet or is mopped up. Some drains into Lake Hood, airport officials said.
Propylene glycol can harm fish when it leaks into streams or lakes. As the fluid biodegrades, it reduces the amount of oxygen in the water, according to the U.S. Environmental Protection Agency. That likely is the reason for a few fish kills that have occurred at airports, the EPA says.
The fluid's aquatic harm is not the reason state officials want to add the fluid to their list of regulated chemicals. The state wants to list the chemical and establish human health-based cleanup levels so it will know how much to remove from a contaminated area after a spill, Janes said.
However, aquatic concerns are driving EPA officials to consider new regulations of their own.
Federal regulators have informed the airline industry that they will propose to limit effluent from anti-icing and de-icing fluids next year.
The rules will likely be in place by 2009, according to an EPA Web site.
Officials at the Anchorage airport said Friday they are trying to get out ahead of the new federal rules.
During the past few years, the airport has diverted most of the de-icing fluid that used to drain to Lake Hood, said Shane Serrano, the airport's environmental program specialist.
The airport water pollution permit does not limit the amount of de-icing fluid that drains to Cook Inlet. However, future EPA guidelines could change how the airport is regulated, Serrano said.
The rules also could affect rural airports. Many do not have a drain system for collecting the de-icing fluid or a system to mop it up, state regulators said.
"We recognize that money is short and we cannot suddenly start requiring infrastructure at rural airports," Janes said.