i Reilly Tar & Chemical Corp. (St. Louis Park) Timeline (1917-1985)



¦1917

Republic Creosoting Co. begins refining coal tar
and treating wood with creasote at the site. Up
to 6,000 gallons/week of wastewater was
discharged to wetland south of the site.
[Republic bought coal tar from gas plants
throughout Minnesota, and it was refined on the
site. It was a subsidiary of Reilly Industries, which is
now Vertellus Specialties (Vertellus).]

1960s-1970s

The city of St. Louis Park
and the state plug over a
dozen wells that were
conduits for pollution to
groundwater. Soil
contamination found to

depths of 45 feet.

r- 1972

Republic Creosoting
dismantled and land
sold to the city of St.
Louis Park.

1-1978 - 81

The cities of St. Louis Park
and Hopkins close seven
drinking water wells
(SLP4, 5, 7, 9,10,15, and
H3) in the Prairie du
Chien/Jordan aquifer that
were contaminated with
PAHs.

1980

EPA and the
cities of St. Louis
Park and
Hopkins join the
lawsuit against
Reilly Tar.

r 1984

EPA issues cleanup
decision requiring
construction of a
treatment plant at
wells SLP 10 & 15.

I

1932

First St. Louis Park municipal
well drilled and abandoned
due to taste and odors.

I

1940s

Oil/water separator
installed, but effluent
discharge to wetland
continued.

Contamination found
in private wells near
the site.

I

1970

The MPCA files a
lawsuit against Reilly
Tar & Chemical Corp.
(Reilly Tar) forairand
surface water
pollution.

1973

Stormwater collection
system built at the site,
including lined pond.
[Pond still exists. Water
drains eventually to
Minnehaha Creek,
monitored by the city of
St. Louis Park.]

r

1979

28 wells plugged
or reconstructed
to prevent spread
of contamination.

1983

EPA puts the site
on the National
Priorities List.

1985

Reilly Tar constructs
drinking water
treatment plant for the
city of St. Louis Park to
treat water pumped
from wells SLP 10 & 15.

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%



Reilly Tar & Chemical Corp. (St. Louis Park) Timeline (1986-1996)

1986

Reilly Tar signs
multi-party Consent
Decree with EPA, the
state, and the cities.
[The city of St. Louis
Park agrees to share
responsibility for
implementation, with
initial funding by
Reilly Tar.]

- 1987

The city of St. Louis Park began
pumping two additional wells
(well W105 in the
Ironton/Galesville aquifer to
remove contaminated
groundwater near the source
and well W422 in the Glacial
Drift aquifer to help control
groundwater flow). [Well W105
in the Ironton/Galesville aquifer
operated until 1991 and well
W422 until 2000. EPA approved
conversion of both to
monitoring wells.]

1990s

Redevelopment of nearby off-site properties was managed under MPCA's
Voluntary Investigation and Cleanup program. MPCA approves Remedial Action
Plans for safe handling and disposal of contaminated soil encountered.

¦1991

MPCA and EPA establish
contaminated material
safety requirements for
the city of St. Louis Park
construction of highway
interchange south of
the site.

[Interchange is
Hwy 7/Louisiana Ave.]

^1991

The city of St. Louis
Park adds treatment
for PAHs to drinking
water well SLP4.

1995

One additional well
constructed and began
pumping in northern
area of the Glacial Drift
aquifer. [This was well
W439, which continues
in operation today, with
discharge to the sanitary
sewer.]

^1995

EPA and MPCA request
the city of St. Louis
Park re-evaluate
gradient control for
the Prairie du
Chien/Jordan aquifer
to protect drinking
water wells.

1986

EPA issues a site-wide cleanup decision with
actions to protect drinking water and to control
the sources of contamination. Tarry waste was
removed from well W23, and then it was turned
into a source control well in the Prairie du
Chien/Jordan aquifer.Two source control wells
were built - W420 in the Glacial Drift aquifer and
W421 in the Platteville aquifer.

1986

The city of St. Louis Park completes
filling of contaminated wetland south
of site with 2-3 feet clean fill (between
Walker and Lake St.).

[

1990

EPA and MPCA
issue cleanup
decision for the St.
Peter aquifer.
[Required
pumping of well
W410 to intercept
and contain
contaminated
groundwater.]

1991

Methodist Hospital
stops pumping high
volumes from its well,
prompting EPA and
MPCA concern for
potential movement
of groundwater
contamination.

I

1992

EPA and MPCA
issue a cleanup
decision for the
northern area of
the Glacial Drift
aquifer.
[Requires
continued
pumping of well
W422 and at
least one
additional well,
to intercept
groundwater.]

I

1995

EPA and MPCA issue cleanup
decision for northern area of the
Platteville aquifer.

[Requires construction of a new
pumping well. The cleanup was
modified in 1997 to allow use of
well W434 for this purpose. This
well operated until 2006 when EPA
approved shutdown.]

u

1996

MPCA conducts 1 st Five-Year
Review with EPA oversight.
Recommends continued
operation and maintenance of
treatment systems and
groundwater flow modeling and
that EPA and MPCA continue to
monitor development at the site.
[It also made some other more
specific recommendations.]

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%



Reilly Tar & Chemical Corp. (St. Louis Park) Timeline (2000-2014)

2000

EPA and MPCA
approve the city of
St. Louis Park's
feasibility study and
plans for additional
monitoring and
contingency actions
for pumping of SLP6
for gradient control
in the Prairie du
Chien/Jordan
aquifer.

r200i

Apartment complex
constructed south of the site
following a Remedial Action
Plan approved by MPCA.
8,000 cubic yards soil
excavated and treated.

2004

"Block 7" property office building constructed
following EPA and MPCA approval of construction
plan. Passive gas venting system required and
installed to minimize potential for vapor intrusion,
confirmed by air monitoring.

2004

The city of St. Louis
Park constructs
Louisiana Avenue
traffic improvement
projects following EPA
and MPCA approved
protocols for
management of
contaminated soils.

2005

PAHs in the city of Edina
well E13 temporarily
exceed advisory level
but continue to meet
drinking water criteria.

2008

MPCA conducts soil vapor study.
Results indicate further sampling
needed. EPA and MPCA approve
the city of St. Louis Park's plans to
expand water level monitoring to
better evaluate groundwater flow.

- 2009-10

The city of St. Louis Park and
Vertellus (Reilly Tar) decline to
conduct vapor study and EPA
begins preparations.

r- 2013

EPA and MPCA direct the city of St.
Louis Park and/orVertellus (Reilly Tar)
to modify the gradient control system
in the Prairie du Chien/Jordan aquifer.
The city of St. Louis Park submits a
plan for three new monitoring wells
and revised gradient control plan.

I

2001

MPCA conducts 2nd Five-Year
Review with EPA oversight.
Concludes that drinking water
is properly treated. Inspection
finds exposed debris on the site
but no tar substances. Notes the
city of St. Louis Park plans for
addition of clean fill and new
drainage. Recommends
continued pumping and
monitoring of groundwater,
and groundwater modeling to
evaluate gradient control.

r

2002

The city of St. Louis Park
constructs soccer field, light
towers and other
improvements to the park at
the site, following plans
approved by MPCA and EPA.
Includes placement of more
than two feet of clean fill.

2006

MPCA conducts 3rd Five-Year
Review with oversight by EPA.
Concludes that most
Reilly-affected groundwater is
being contained by required
pumping, but recommends
evaluation of increased
pumping to protect the city of
Edina wells. Also
recommended additional
investigation of vapor
intrusion.

2011

MPCA conducts 4th
Five-Year Review with
oversight of EPA.
Protectiveness of the
remedy is deferred pending
completion of vapor
intrusion investigation.

r

2014

Monitoring initiated in three
new Prairie du Chien/Jordan
wells. EPA documents the
results of the vapor intrusion
investigation in a Five-Year
Review Addendum. EPA also
initiates updated
groundwater modeling to
evaluate gradient control.

2011-14

EPA samples sub-slab, indoor, and outdoor air at and near the
site over several seasons for PAHs, VOCs and SVOCs and
concludes that this pathway does not present a health risk.

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