“Think of concrete like a sponge,” said Daniel Lavrich, a structural engineer who chairs the Broward Board of Rules and Appeals, which enforces the building code. “It absorbs water. And a certain amount of that water will go into the concrete and eventually reach the reinforcing steel. And if there’s a high salt content, that salt content is going to attack the reinforcing steel even more than the water. When it rusts, it expands, when it expands, it cracks the concrete. That lets more water in, you get more rust, you get more expansion, and on and on.”