As the wires were being spun, work also commenced on the demolition of buildings on either side of the river for the Brooklyn Bridge's approaches; this work was mostly complete by September 1877. The following month, initial contracts were awarded for the suspender wires, which would hang down from the main cables and support the deck. By May 1878, the main cables were more than two-thirds complete. However, the following month, one of the wires slipped, killing two people and injuring three others. In 1877, Hewitt wrote a letter urging against the use of Bessemer steel in the bridge's construction. Bids had been submitted for both crucible steel and Bessemer steel; John A. Roebling's Sons submitted the lowest bid for Bessemer steel, but at Hewitt's direction, the contract was awarded to Haigh.