Q.: A customer of ours developed severe chemical burns on his knees when placing concrete in his hog barn. These burns may eventually require skin grafts. The concrete mix he was using contained 2 percent calcium chloride. Could the calcium chloride have aggravated the burning action of the concrete?

A.:All concrete can eat away, or dissolve skin. Calcium chloride has little or no effect on this action. Concrete burns are insidious; often the victim is unaware that anything is happening until the action is far advanced. For this reason ready mixed concrete producers are beginning to issue warnings to users about the dangers of exposing skin to concrete and to describe precautions and remedial measures to take. For good suggestions on this, see the article by William G. Hime, "Let's Stamp out Concrete Burns," Concrete Construction, April 1982, page 361.