Maryland motorists will find winter driving a little less slippery on certain highways thanks to a chemical from the Dead Sea.
Officials at the State Highway Administration have decided to expand their use of magnesium chloride to melt ice and snow. Last year, SHA crews tried it for the first time with dramatic success.
"This stuff will work at 13 degrees below zero," marveled Gail A. Courtney, the SHA's deputy chief engineer for maintenance. "It keeps the highway clear when salt alone doesn't do much. . . ."
Snow removal crews in Northern Baltimore County experimented with magnesium chloride last winter on Interstate 83 near the Pennsylvania state line. The results were so impressive that the SHA will try it again on I-83 and at four sites in Western Maryland.
That should be welcome news to motorists who suffered through the worst driving in memory last winter. The series of ice storms that hit the region exhausted salt supplies and cost the SHA and their local counterparts millions of dollars.
Magnesium chloride, which occurs naturally in seawater, is the prime component in a de-icing fluid sprayed on loads of salt or mixtures of salt and abrasives such as crushed stone, slag or sand. About 30 gallons of the fluid cover an 8-ton truckload of salt, Mr. Courtney said.
Salt, properly known as sodium chloride, will not melt ice once the temperature falls below 20 degrees. Calcium chloride mixed with salt is effective to 0 degrees, but it is caustic and difficult to handle.
During last winter's experiment, portions of I-83 were clear when other roads in the area were still covered with ice, Mr. Courtney said. Crews also found that salt treated with the magnesium chloride de-icer was less likely to be swept off the roadway by traffic.
"All the [snow removal] drivers were asking for it," Mr. Courtney ,, said. "This year, we are going to have a very controlled experiment to see how cost-effective it is."
The SHA plans to use the same de-icing technique to treat highways around Keysers Ridge, Thurmont and LaVale, and on U.S. 40 at the Washington County-Frederick County line.
The Dead Sea is the largest supplier of magnesium chloride, although some is also produced at the Great Salt Lake. The material costs the state about 62 cents a gallon. Salt costs $25 to $30 a ton.
SHA officials yesterday released a summary of last winter's cost. Keeping state highways clear of snow cost $23.8 million over the past year compared with $16.9 million the year before and $8.3 million in 1992.
The state needed 234,000 tons of salt compared with the 150,000 tons required in an average winter.
Hal Kassoff, SHA's administrator, said the agency now has 200,000 tons of salt stored for the season and is prepared for the worst.