1920s: Puget Sound shellfish growers sound the alarm over pollution from pulp mills.
1945: State office is created to control pollution - the Pollution Control Commission.
1960s: Pulp mills and other industries begin to treat toxic waste discharged into Puget Sound.
1970: State Department of Ecology is created to oversee statewide pollution control efforts.
1972: Congress passes federal Clean Water Act.
late 1970s-early 1980s: Shellfish bed closures, tumors in Puget Sound bottomfish, declining salmon runs, gray whales' washing ashore and listing of Tacoma tideflats as a federal Superfund site all raise concerns that Puget Sound is in trouble.
1985: Puget Sound Water Quality Authority formed to draft a Puget Sound water quality management plan.
1987: First water quality plan for Puget Sound is created.
1992: State law is passed requiring local governments to form shellfish protection districts and create cleanup plans when pollution closes a shellfish-growing area. Law doesn't require the cleanup plan to be enforced.
1996: Puget Sound Water Quality Authority is disbanded and replaced by less autonomous Puget Sound Action Team, which is housed in the Governor's Office.
1999: Puget Sound chinook salmon is listed as threatened under the federal Endangered Species Act.
2002: Late summer oxygen levels plummet in lower Hood Canal, triggering fish kills and deaths of other marine life.
2005: Puget Sound orca whale population is listed as endangered under the federal Endangered Species Act.
2005: Legislature approves $52 million requested by Gov. Chris Gregoire to kickstart a plan to clean up and restore Puget Sound health by 2020.
December 2005: Gov. Chris Gregoire announces a new environmental initiative to restore Puget Sound to a clean, healthy condition by 2020.
2007: State Legislature creates the Puget Sound Partnership, a new state agency to oversee the cleanup of Puget Sound.
September 2008: Deadline for Puget Sound Partnerhsip to complete a cleanup action plan for Puget Sound.