Ind. 49 north of
the U.S. Highway 20 interchange in Porter was closed late Tuesday
afternoon--and will remain closed for at least another day--after the newly
paved road surface began weeping a greenish ooze smelling strongly of
sulfur.
That ooze is
believed to be the product of a chemical reaction between the slag base used
by INDOT, ground water, and the recent high temperatures.
Breathing the
rotten-egg stench sent two first-responders to hospital on Tuesday for
treatment of headache and nausea, and the propensity of some people to be
made physically ill by the odor has prompted the Porter County Environmental
Department to order Ind. 49 closed.
The ooze was first
noticed shortly before 5 p.m., Porter Deputy Fire Chief Jay Craig told the
Chesterton Tribune today, in the northbound lanes of Ind. 49 directly
opposite South Bailey Drive. In perhaps 10 places along a 200-foot stretch
of the fresh pavement a light green seepage resembling antifreeze was
observed and in fact the first on the scene, a Porter Police officer, was
responding to a report of an antifreeze leak.
That officer was
subsequently transported to hospital complaining of headache and “a funny
taste in the mouth,” Craig said.
Also transported
was Porter Fire Chief Lewis Craig, who experienced shortness of breath and
nausea after being exposed to the odor.
The officer and
Chief Craig were both later released. The latter told the Tribune
just before deadline that he’s feeling fine.
In the 12 hours or
so after the seepage was first discovered, the stuff has been tenatively
identified as ground water--or else runoff from recent rains--chemicallly
reacting with the slag in the road base.
Slag is a leftover
of the steelmaking process, produced when iron ore is reduced to molten
iron. Allowed to cool, it “becomes a light gray vesicular rock,” according
to the National Slag Association’s website, and is commonly use for road
base, fill, and embankments, among other things.
Slag has become a
particularly popular material in road construction here in Northwest
Indiana, Craig said, and indeed the Indiana Department of Transportation
touts its use on the agency’s website, as one of the “waste materials” it
recycles in road construction and reconstruction projects “to save resources
and cut costs.”
Craig noted that
the past week’s heavy rains have very likely caused the water table beneath
the affected stretch of Ind. 49 to rise much higher than it was when INDOT’s
contractor first laid the slag base some months ago. Meanwhile, the
brand-new blacktop has been absorbing the recent high temperatures and
probably heating the ground water below. Those two factors are believed to
be the cause of the chemical reaction. A similar incident is said to have
occurred on I-65 “many years ago,” Craig said.
Last year the
Chesterton Town Council amended Town Standards to permit developers for the
first time to use slag--instead of more expensive limestone--as a road base.
Municipal specifications, however, require the slag to be INDOT-certified,
that is, washed and processed. Town staff had previously recommended against
the use of slag due precisely to a strong odor which was sometimes known to
waft through neighborhoods via storm sewers. Washed and processed slag is
supposed to be odor-free.
Persons familiar
with the use of slag in road construction told the Tribune this
morning that it’s conceivable an improperly washed batch of slag ended up
beneath the asphalt of Ind. 49. It’s also possible, though, that the slag is
perfectly fine and some mineral or other substance in the ground water is
just reacting with it.
Whatever the cause,
the solution is going to be complicated. Today INDOT had retained the
services of an environmental contractor to clean up and contain the seepage,
which Craig said dries to a chalky or milky white color. A vacuum truck has
been deployed to the scene.
Going forward, the
idea will be to finish paving the two southbound lanes of Ind. 49 north of
the U.S. 20 interchange as soon as possible so as to open one lane each to
south- and northbound traffic. Then the whole affected stretch of the two
northbound lanes will have to be ripped up and the road rebuilt using a
limestone base, Craig said.
Also responding to
the scene, at one time or another after the seepage was discovered, were the
Chesterton PD, the Porter County hazmat team as well as the LaPorte County
team, a ranger with the National Park Service, a conservation officer with
the Department of Natural Resources, and Porter Regional Hospital EMS.