Highway departments and airports need some substance that will melt ice from roads and runways so that the traffic may continue to flow safely when winter storms hit. Here are some options that are available:

Road salt costs about $30 per ton, and it works fast. More than 10 million tons are spread each year in the US. It is corrosive to concrete, asphalt, and metal, thus eating roads, bridges, and car bodies. It contaminates drinking water and kills trees and plants. Studies suggest that this damage costs from $600 to $1000 per ton of salt to correct. Calcium magnesium acetate, a commercial deicer, is made from limestone and vinegar. It costs $640 per ton and takes about 15 minutes longer than salt to melt large ice patches. It usually lasts somewhat longer. Scientists think it may actually do some good for soil and plant life, and is not corrosive.

Contrast financial cost and social cost involved with using these products. Which cost should be used for government decision making and why?