The site of the park was previously occupied by a wood treatment plant and (according to the Port of Seattle) a shipbuilding facility. The wood treatment plant operated from 1909 to 1994. It was successively owned by the J.M. Coleman Company (1909); West Coast Wood Preserving Company (jointly owned by J. M. Coleman Co. and
Pacific Creosoting) (1930); Baxter-Wyckoff Company (1959); Wyckoff Company (1964); and Pacific Sound Resources (1991) before passing to the Port of Seattle (1994), having been determined to be contaminated with
creosote and designated a
Superfund site by the
U.S. Environmental Protection Agency in 1994. To the east of the creosoting plant, also within the park boundary, was the Nettleton (originally Schwager Nettleton) Saw Mill and Lumber Yard, which operated from 1910 until 1965. Originally named Terminal 5 Park, the park opened in 1998 as part of the Port of Seattle's redevelopment of Terminal 5 and was dedicated and named after former Port Commissioner Jack Block in 2001. In 2007 a local community group proposed a plan to move the West Seattle terminal of the
King County Water Taxi from
Seacrest Park to Jack Block Park, but as of 2012 the plan has not been implemented. After an environmental cleanup effort that included the removal of contaminated mud and wood pilings as well as the
capping of of sediment, the park's beach opened to the public in 2011. ==Activities==