History of PFAS in Woodbury
Per- and polyfluoroalkl substances (PFAS), a large family of many fluorinated compounds, are used by several companies around the world in household and industrial products such as stain repellents, lubricants, fire retardant and suppressants, and more. PFAS wastes from a manufacturing site in Cottage Grove, Minn., were disposed of at various locations in Washington County. The source of PFAS in Woodbury’s groundwater has been identified as these disposal sites.
Below is a general timeline of PFAS-related activities in Woodbury since 2005, when the Minnesota Department of Health (MDH) began testing Woodbury wells for PFAS.
MDH begins testing Woodbury’s wells for PFAS after low levels of PFAS were detected in private wells in western Lake Elmo. Monitoring of Woodbury groundwater production wells continues today.
PFAS detected at low levels in Woodbury wells. MDH establishes a health risk level for some specific PFAS. Woodbury’s wells test below the health risk levels.
The State of Minnesota and 3M reach a settlement agreement that provides the state $40 million for temporary water treatment projects relating to PFAS in the east metro.
The Minnesota Pollution Control Agency (MPCA) and 3M complete additional remediation activities at the disposal sites.
Long-term site groundwater management and remediation continues to limit remaining contamination to the sites.
Due to advancements in detection technology, trace levels of other PFAS are found in Woodbury wells. However, the concentrations detected remain below the health risk limits established by MDH.
The U.S. Environmental Protection Agency (EPA) reduced its drinking water protective guidance level for some PFAS to 70 parts per trillion. EPA studies indicate exposure to certain PFAS at high levels may result in an increased risk of adverse health effects.
MDH announced it was reviewing studies and methods used by the EPA to determine whether its own health risk levels need to be lowered and, if so, what the values should be.
MDH completed its review and updated its protective guidance level for some PFAS. The new risk levels, based on daily consumption over a lifetime, were reduced further from the EPA 70 parts per trillion guidance. MDH scientists updated the values to better reflect new state-level analysis of the potential for mothers to pass along the chemicals to fetuses and nursing infants.
MDH issues health risk advisories on five of city’s 19 wells with PFAS levels above water quality standards and guidelines. The city makes operational changes, significantly reducing the use of these five wells.
The State of Minnesota and 3M reach a settlement agreement and the state receives a grant from 3M for $850 million. After legal fees, approximately $700 million remains for assisting east metro communities in cleaning up its water supply.
The State of Minnesota begins to study long-term water treatment options in the east metro that will be funded through the $700 million settlement grant.
MDH lowers health-based advisory value for PFOS again from 27 parts per trillion (set two years ago) to 15 parts per trillion and sets a guidance value for PFHxS.
The MDH issues a health risk advisory on a sixth Woodbury well. All six Woodbury wells with health risk advisories are taken out of service.
City of Woodbury receives approval to begin design on a temporary treatment facility to treat three of the current six wells out of service for PFAS impacts.
The Woodbury City Council declares a local emergency to expedite the construction of a temporary water treatment facility to treat three of the six wells with health advisories. Project funding is coming from the 2007 Consent Decree agreement between the State of Minnesota and 3M. City begins work with its consultants to design the treatment facility.
MDH issues a health risk advisory on a seventh Woodbury well due to PFAS levels. The well is immediately taken out of service. In addition, construction begins on the new temporary water treatment facility to be located north of Valley Creek Road and east of Tower Drive.
The Woodbury temporary water treatment facility is brought on-line for sustained water treatment and production on four of the seven wells removed from service due to detected levels of PFAS. The water treatment facility can produce approximately 4,500 gallons per minute of water meeting all current state and federal standards and guidelines for PFAS.
The city begins planning for the expansion of the temporary water treatment plant capacity, which may be needed until the long-term treatment facility is fully operational.
Design development begins for Well 20 construction. Well 20, following construction, will provide increased capacity in water production to meet city growth and temporarily offset a portion of lost capacity due to PFAS impacts until long-term treatment is in place.
State of Minnesota releases its long-term Water Supply Plan to address PFAS contamination in the east metro area. The most important outcomes in the plan for Woodbury include: funding the land acquisition and construction for a long-term water treatment facility; funding the replacement of one of the city’s existing public water production wells (permanently off line due to location and PFAS impacts); funding/supplying homes on private wells with PFAS impacts with standalone point-of-entry treatment systems for PFAS removal; and funding connections of other properties currently with private wells with PFAS impacts to the city’s public water system due to proximity of water mains.
The City of Woodbury closes on the purchase of land south of Hargis Parkway and east of Radio Drive for future construction of a long-term water treatment facility.
The city initiates consultant selection and grant development for funding of preliminary engineering and piloting for the long-term water treatment facility.
The city begins drilling of Well 20 to meet growth and water demand. The same month, the city initiates expansion of the temporary water treatment plant with receipt of preemptive order of treatment equipment.
MDH issues a health risk advisory on an eighth Woodbury well due to PFAS levels. The well is immediately taken out of service.
MDH issues a health risk advisory on a ninth Woodbury well due to PFAS levels. The well is immediately taken out of service. In addition, piloting of treatment technologies for the long-term treatment facility is initiated.
Design development begins for Well 21 construction. Upon completion, the well will provide increased capacity in water production to meet city growth, temporarily offset a portion of lost capacity due to PFAS impacts until a long-term treatment plant is in place, and permanently replace one well taken off line and abandoned due to PFAS impacts.
Expansion of the temporary water treatment plant is substantially complete allowing for the treatment of six wells with health risk advisories.
DNR seeks public comment on Well 20 appropriation approval. In addition, Phases 1, 2a, and 2b of the pilot study are complete and the city receives approval to implement phase 3a and 3b of the effort.
Woodbury receives MDH approval on Well 21 construction and staff moves to implement drilling by end of month.
Woodbury places advanced order for equipment for additional temporary treatment capacity.
Woodbury is awarded federal funding for the Well Manifold Pipeline Project.
Well 2021 bore hole is completed; The well is anticipated to be online in the summer2024.
MPCA approves 75% funding for permanent Woodbury Water Treatment Plant design. The city contracts with a design engineering team.
Well 20 is put into service.
EPA issues draft Maximum Contamination Goals (MCLs) for two PFAS compounds that may substantially impact Woodbury’s water system in the future.
MPCA approves remaining 25% funding for permanent Woodbury Water Treatment Plant design.
MPCA approves grant funding for construction of three interim water treatment plants. Design development begins for these three facilities.
The city receives a health advisory from MDH on a tenth water production well. As part of the city’s ongoing management of the water system, the well remains available for service to meet short duration peak water demand in the summer months. However, operationally it is placed low in use order, eliminating its use on most summer days and limiting its use on those days of peak demand. It is one of three wells that will receive on-site interim well treatment for PFAS by 2024 and used until the permanent water treatment plant is operational.
Construction of the three interim water treatment plants is expected to begin.