Fardin Oliaei, the MPCA's lead researcher on PFCs, warns two Health Department officials about preliminary tests that show high levels of PFBA in soil and water samples from the Washington County Landfill. PFBA is a chemical once made by 3M for photographic film.
Oliaei urges them to test residents' wells for the chemical. She says she was ignored. The Health Department officials cannot recall having the conversations with Oliaei.
Final results of Oliaei's tests confirm high levels of PFBA in the Washington County landfill. The Health Department begins developing its own test for PFBA in drinking water, and those tests begin in 2006.
Legislative hearings look into the state's response to PFCs. MPCA Commissioner Sheryl Corrigan, a former 3M manager, twice refuses to appear, saying she has recused herself from agency matters involving 3M.
Fardin Oliaei's studies of fish from the Mississippi River show the presence of some of the highest levels of PFCs found anywhere in the world.
Fardin Oliaei says she is forced out of the Minnesota Pollution Control Agency after she publicly urged a wider investigation into PFCs. The MPCA says her departure was voluntary and the result of a mediated settlement over a lawsuit she brought against the agency. Minnesota Department of Health puts new fish consumption advisories in place on the Mississippi River, based on studies Oliaei conducted for the MPCA, based on fish samples collected by 3M.
A group of scientific advisers to the EPA recommend that PFOA be considered a likely carcinogen.
MPCA Commissioner Sheryl Corrigan resigns. Gov. Pawlenty replaces her with former DNR official Brad Moore. Moore promises to bring "transparency" to MPCA actions on PFCs.
The Health Department says PFBA is contaminating drinking water in several east Twin Cities metro communities, including Cottage Grove and Woodbury.
3M officials tell a legislative committee a person would have to drink hundreds of thousands of glasses of water a day to notice any effects from PFBA. Health Department officials say such statements are "dangerous."
MPCA Commissioner Brad Moore declares his agency's intention to declare releases of PFOA and PFOS "hazardous" under Minnesota's superfund law. He says the designation means the MPCA will have more legal tools to persuade 3M to clean up PFC contamination at three locations, including the company's Cottage Grove plant. The matter now goes before the agency's citizen board later this month. 3M says it will challenge the action.
MPCA engineer Don Kriens produces new calculations that shows approximately 73,000 pounds of PFCs entered the Mississippi River each year from the 3M Cottage Grove plant, prior to installation of a filtration system in 2004.
3M and the MPCA fast-track a plan to control PFC waste spreading from 3M's plant in Cottage Grove, where it has been buried. The plan calls for a cap over the site. MPCA's Don Kriens says the cap will not prevent the movement of contamination from the plant site into the river.
In response to new information on the health threat posed by PFOA and PFOS, the state lowers health limits for those chemicals. The Health Based Values for these chemicals have been revised downward twice.
Originally they were set at 7 parts per billion for PFOA and 1 part per billion for PFOS. They were lowered to 1ppb and to .6 ppb, respectively. And in March 2007, those values were reduced again, to .5 ppb for PFOA and .3 ppb for PFOS.
Oakdale city officials learn that charcoal filters are not good at removing PFBA from the water. Within six weeks of opening its Oakdale water filtration system, PFBA began to leak through the lead water filters.
Oakdale officials meet with 3M to get clearance to begin looking for a new well location. The city is only operating two of its eight wells right now. They will have to start using some of its other contaminated wells this summer, unless the city can drill a new, larger well to replace them.
The Minnesota Department of Health issued new fish consumption advisories after finding elevated levels of PFOS in bluegills from Lake Calhoun and in Mississippi River fish as far south as Winona on April 16. The average level of PFOS among the five bluegills tested was 319 parts per billion. The Department recommends no more than one meal of bluegills per month from Lake Calhoun. Its recommendations vary for fish in the Mississippi River. The guidelines can be found on the agency's Web site.
The Minnesota Pollution Control Agency's Citizen's Board postponed MPCA Commissioner Brad Moore's request to declare the release of PFOA and PFOS as hazardous substances on April 24. Instead the board instructed Moore to try to negotiate an agreement with 3M to clean up the contaminants. If 3M and the Commissioner can't come up with an agreement by the board's May meeting, members say they will vote on the hazardous substances designation.
MPCA will begin looking for PFCs in open landfills and wastewater treatment discharges in 2007.
The MPCA also plans to begin testing to see if 3M is releasing PFCs into the air at its Cottage Grove plant.