Don Ferguson likes this kind of weather. Cold, wet, sloppy. You know, miserable.
He likes this kind of weather because it's good for business. Ferguson is a sales manager for Cargill Salt. Salt as in rock salt. As in de-icing salt. As in please-for-the-love-of-God-make-this-street-passable-again salt.
FOR THE RECORD - In an article in the Today section on Feb. 23, The Sun misreported the amount of rock salt the city of Baltimore had on hand as the winter season began. The correct figure was about 19,000 tons. The Sun regrets the error.
Cargill, based in Minneapolis, is one of two suppliers of salt to the city of Baltimore. Ferguson was one of several helpful sources for the following primer on rock salt, stuff no normal person ever thinks about until you find yourself fishtailing your way down (or across) the JFX.
Amount of salt Baltimore City has on hand: About 136,000 tons. (Baltimore County has 34,000 tons, and the Maryland Highway Administration has 234,000 tons, in case you're interested.)
Amount of salt Baltimore City uses: It all depends on the weather. Duh. In the year 2000, the city used 24,000 tons of the stuff. In 1998, it used only 572 tons. The most used in recent history was in 1996 when the city spread 37,000 tons on the roads. That same year, the state put down 406,000 tons.
Number of trucks the city uses for salt dispersal: 188 large dump trucks and 59 smaller, one-ton trucks.
What it is: Sodium chloride.
Its chemical formula for those aficionados of the Table of Periodic Elements: NaCl.
Where it comes from: Everywhere.
Please be more specific: The salt used in Baltimore comes from several sources. A lot of it is shipped to the port of Baltimore from mines in a coastal desert area of Chile that was once part of the ocean bed. Evaporation left natural salt deposits.
Some of it also comes from Ohio mines and also a solar salt facility in the Baja Peninsula where ocean water is put into pools to allow the sun to do its work.
Its cost: Usually between $25 and $50 a ton.
Can I use it in my soup: Not advisable, although you could. One thing for certain, your gumbo would be a lot grittier. Table salt comes from the same places as rock salt but is refined to be purer. Rock salt is usually between 95 and 99.5 percent pure. Table salt is closer to 100 percent pure.
What rock salt does when it hits the roads: Salt lowers the freezing point of water. The greater the concentration of salt, the lower the freezing point, although there is a cellar temperature below which it doesn't work well. Happily, Baltimore winter temperatures, usually no colder than the 20s, are just about perfect for salt's effectiveness. If it does get colder, there are chemicals that can be added to the salt to help it work better.
How do you know when to use the salt: Look out the window. That's one way, of course. But many municipalities as well as the state of Maryland also make use of sensors that gauge air and surface temperature as well as the amount of salt presently on a roadway. That helps tell crews the places that need attention.
Environmental impact: Environmentalist aren't in love with salt because run-off can increase the salinity of waterways and disturb aquatic plant and animal life. But the Chesapeake Bay Foundation says the state generally does a responsible job of storing salt - it should be covered to prevent run-off - and of dispersing it. The group has detected very little impact on the bay or elsewhere.
What's not to love: Rust. Salt can corrode your car if you don't get out there and wash it off. But, hey, the exercise will make the gumbo taste better.
