A transformation is taking place this week at East Helena's idled Asarco smelter, with a Maryland company turning a highly volatile chemical into a product that will be used to treat tainted water at the plant.

The closely controlled chemical reaction, which will take about a week, will not pose any threat to the nearby community, according to those familiar with the process.

"The worst that could happen would be that we would have a large emission of sodium hydroxide. That probably wouldn't get to the road (between Asarco and East Helena) and if it did it would just be an irritant for breathing," said Kevin Beaver, a chemical engineer with Creative Engineers Inc. of Maryland. "But it's hard to imagine even that happening."

Creative Engineers contracted with Asarco earlier this year to dispose of the sodium metal that's been sitting in a double-walled railroad tanker car at the East Helena plant since about 1988.

Asarco had used the sodium in its dross plant from August 1988 through October 1991 to enhance the recovery of antimony and silver.

However, the fact that it was being stored on site wasn't known to officials with the state Department of Environmental Quality until the tanker was discovered during a routine inspection in August 2004.

The one to two tons of sodium metal in the tanker greatly concerned DEQ and EPA officials, because sodium metal is a flammable solid that can catch fire when exposed to air and may ignite spontaneously, accompanied by explosions that can cause spattering of molten material.

DEQ officials had wanted Asarco to get rid of the tanker and its contents by last September, but Asarco officials argued that it been safely stored for more than a decade and they wanted more time to consider various options.

State officials are still considering whether to pursue any penalties against Asarco for dragging its feet in getting rid of the tanker's contents. But for now, they're pleased that the potential hazard is being defused.

"(Creative Engineers) are knowledgeable and experienced," said Mark Hall, DEQ hazardous waste section supervisor. "We're confident in their ability to get this done."

The plan calls for Creative Engineers to pump nitrogen and steam into the tanker to purge all oxygen from it. The moisture from the steam will react with the sodium metal, which will create about 5,000 gallons of sodium hydroxide — a corrosive Drano-like substance that can be purchased at any hardware store, according to Berry.

"It's a weak solution, but it's still corrosive — you don't want to get it on your hands," Berry said.

He added that although you wouldn't normally want to pair sodium metal with moisture because of the potential for explosion, the lack of oxygen makes this a safe process.

"If it's completely oxygen-free, even if you squirt water in there it wouldn't explode," Berry said, adding that the tank is un-pressurized and closely monitored. "This is a very controllable reaction."

About 100 to 300 pounds of sodium will be reacted per hour, with the entire reactive process expected to take about three days. Flushing the tanker will take a few more days.

The sodium hydroxide will be stored at Asarco until it's needed to neutralize acid wastes in water that becomes contaminated when it flows through the plant during high runoff, according to Asarco Environmental Manager Jon Nickel. The company already has a water treatment plant on site.

"We already purchase sodium hydroxide for this process, so it's nice that we can use what's being generated from the tanker," Nickel said on Tuesday. "We use it to (remove) metals in storm water that we collect."

Small amounts of nitrogen, hydrogen and steam used in the process will be vented through a "scrubber" to rid it of any harmful chemicals.

Creative Engineers developed this procedure to safely treat sodium metal, and has conducted similar operations around the world since 1997. Two experienced operators will be on site at all times once treatment begins.

At the end of the process, the clean tanker will be allowed to remain at Asarco, according to Hall.

"They may have a use for it on site, they can cut it into scrap metal or it can be used as a tank again," Hall said.

Reporter Eve Byron can be reached at 447-4076 or eve.byron@helenair.com