January 1, 1870 – Company organized in a new firehouse at 456 West Fourth Street , South Boston, near the intersection of Dorchester Street, adjacent to the firehouse of Engine Company 1 at 119 Dorchester Street.
March 3, 1870 – Company received a new Hunneman ladder truck, equipped with 16 ladders of varying lengths.
May 1, 1889 – Company status changed from Call to Permanent status.
November 4, 1902 – Company again received the 1870 Hunneman ladder truck, after being rebuilt by Charles Waugh & Co. The truck was equipped with 17 ladders of varying lengths.
June 20, 1917 – Company received a new 1917 Seagrave, Model ‘756’, 75ft wood aerial ladder truck, Serial # 16554, Shop # 221 , replacing the horse-drawn ladder truck. The company moved around the corner into Engine 1’s firehouse at 119 Dorchester Street. The firehouse at 456 West Fourth Street was closed.
December 4, 1929 – Company received a 1921 American LaFrance, Type 17, tractor, Serial # 3616, Shop #208T attached to the 1917 Seagrave 75ft wood aerial trailer, Shop # 221.
1930 – Company received a 1927 American LaFrance, Type 17, tractor, Serial # 6123, Shop # 250T , attached to a 1915 Seagrave 85ft wood aerial ladder trailer, Shop # 208.
June 17, 1949 – Company received a new 1949 FWD, Model F-85, 85ft wood aerial ladder truck, with 150g. booster tank, Serial # 73193, Shop # 207.
May 25, 1954 – COMPANY DEACTIVATED.
January 8, 1975 – COMPANY REACTIVATED. Ladder Company 5 was reorganized at the quarters of Engine Company 55 at 5115 Washington Street , West Roxbury. Company was assigned a 1950 Mack, Type 85, 65ft. junior aerial ladder truck, with 150g. booster tank, Serial # 85LS-1418, Shop # 232.
General Order announcing Ladder Co. 5 in service, in 1975.
1976 – Company received a 1968 American LaFrance 100ft aerial ladder truck, Serial # 12-1-933, Shop # 234.
April 11, 1977 – Fire Fighter Hugh F. O’Brien, Ladder Company 5, died in the Line-Of-Duty while operating at a brush fire near Bellevue Hill, West Roxbury.
April 10, 1981 – COMPANY DEACTIVATED.