3% grade west to east. The west portal was worked on first since it was a lower grade. On June 21st, the holes were drilled and the arch section was added shortly after. Operations were handled by two shifts of two crews each. Each drilling crew was made up of twelve drillers, twelve suckers, two scaling miners, and one boss. A 30-inch metal ventilating line was installed in each bore suspended at the height of 7 feet above the tunnel floor. The two tunnels ventilation formed a Y which at the base would contain a 36-inch reversible fan. A concrete ventilation shaft was built which is located midway between the tunnels. There is a control room at the base of the shaft. The fans in the shaft would exhaust bad air from the tunnels and blow it up into the shaft out of one of the four ducts. The fans are controlled by carbon monoxide detectors. The tunnel's lighting system was designed to meet both day and night conditions with lights being located on the center line of the roof. Caution and stop lights were installed for emergency use. Removal of any fire extinguisher would automatically change the lights and start the ventilating fan. One life was lost during the construction of the tunnel. The tunnel opened to traffic on November 1, 1949. Notes References Buildings and structures in New Haven, Connecticut Transportation buildings and structures in New Haven County, Connecticut Tunnels completed in 1949 Tunnels in Connecticut Road tunnels in the United States