New safety concerns are surfacing about the new Tappan Zee Bridge after a piece of equipment collapsed and brought construction temporarily to a halt.

Three silos toppled like dominos on one of two floating concrete plant barges at the construction site yesterday. The silos, big tube-like structures, hold the raw materials that make up cement.

A spokesperson for Tappan Zee Constructors, the group that is building the new $3.9 billion bridge, says a failure in the one concrete storage silo tipped and caused two other silos on the barge to bend and collapse as well. Concrete pumping has been suspended at the remaining plant, but construction has resumed on the span.

Tappan Zee Constructors sent out a written statement that reads in part, "All workers are safe and representatives from the New York Department of Environmental Conservation and engineers from TZC and the New York State Thruway Authority are on the scene assessing the situation. Safety and environmental stewardship are our top priorities as we continue to investigate this incident."

According to the Department of Environmental Conservation, no cement spilled into the river.