The safety project focuses on construction of a massive structure called a caisson in Dearborn, Mich., that will help keep the Rouge River clean after heavy rains. The agreement was made between the State of Michigan, unions and a Detroit-based construction company, Walbridge Aldinger, that will oversee the $34-million project.

"Our main concern is to get people home safe to their families," said Mike Davis, head of the Michigan Regional Council of Carpenters and Millwrights, the state's largest construction union, which was part of the agreement signed in Dearborn.

The project involves constructing a watertight chamber 110 feet below the soil of Dearborn and 15 feet from the Rouge River.

Once the container is built, excess water can be stored there, helping to prevent the pollution of the Rouge River, which extends through metro Detroit.

Construction risks include falls, exposure to gases within the soil, and the use of heavy equipment. The agreement calls for special worker safety classes, the monitoring of 21 subcontractors, and for Walbridge Aldinger to report regularly to the state Department of Labor and Economic Growth.

"It's about the culture" of the workplace, a company official said at the signing of the agreement in Dearborn's City Council Chambers.

At the signing, a banner in front read: "If it is not safe, I won't do it and I won't let others do it."