PLAINFIELD TOWNSHIP, Mich. (WOOD) – A timeline of Wolverine Worldwide’s sludge dumping history and the resulting investigation into PFAS concerns:

1939: Wolverine starts dumping at the House Street NE site in Belmont.

1958: Wolverine starts using Scotchguard on pigskin to make shoes at its tannery in Rockford.

1959/1960: House Street neighbors complain about Wolverine sludge. Kent County Health officials investigate, but no laws are created to stop the dumping.

1970: Wolverine notifies Kent County that it will send waste to the Northeast Gravel Company (now the site of Boulder Creek golf course).

2000-2002: 3M, the primary producer of PFAS, phases it out after safety concerns are raised.

2004: A master plan for Plainfield Township parks identifies the House Street dump site as place not to build a park because of potentially hazardous contamination.

2005-2014: Plainfield Township allows construction of seven homes, along with the Belmont Armory, with wells near an old dump. Tests did not check for PFAS. Other homes have been built since.

May 2016: The EPA sets a PFAS advisory level for drinking water at 70 parts per trillion.

January 2017: A Rockford citizens group notifies the state of the potential of PFAS at Wolverine’s House Street dump. Tests east of dump find low levels of PFAS.

May 30, 2017: The Belmont Armory on House Street switches to bottled water after tests find high levels of PFOS in well water.

Mid-July 2017: Tests start at homes south of the House Street dump. Tests now show it has spread more than two miles. So far, there are 30 wells with PFAS over the EPA limit; another 180 have lower levels.

October 2017: Wolverine announces it will provide whole-house filters to more than 300 homes near the House Street dump.

November 2017: Target 8 reveals that 3M, the maker of Scotchgard, warned Wolverine of potential problems with PFAS in 1999. Wolverine had said it learned only recently that Scotchgard contained PFAS.

November 2017: Tests find 490,000 ppt of PFAS in groundwater at the former Rockford tannery site, more than 12,000 in Rogue River sediment and lower levels in river surface water.

November 2017: Gov. Rick Snyder announces a Michigan PFAS Action Response Team to respond to PFAS at Wolverine and other sites in state.

November 2017: Kent County asks the State for EPA help. The State says it is working closely with the EPA.

November 2017: Residents file first lawsuits against Wolverine. Many more are expected to follow.

November 2017: The State says locations of 20 dump sites around northern Kent County have been turned over to Wolverine for further testing.