[1][2][3] He was mortally wounded by a falling wall on November 22, 1848, suffering a severely fractured skull and other injuries.
[4][5] Thornton was inside a burning office building near the southeast corner of Church and King streets, where he was hit by falling masonry.
[1][4] Plummer noted that Thornton was brought to the fire hall for treatment by Dr. Walter Telfer, who cleaned his wounds and treated him with a phlebotomy—bleeding.
Plummer reported that, according to The Globe and Mail [sic] "About two inches square of the skull was driven into the brain,".
In June 2015 a recommendation was made to Toronto City Council that when Toronto Fire Services replaced the Sora with another former Canadian Coast Guard vessel, the Cape Hurd, as its second string fireboat, she should be christened the William Thornton in remembrance of him.