Nine of the 15 companies responsible for releasing the most chemicals into Lake Michigan surpassed government limits of one or more substances in the last six years, an eight-month Times investigation revealed.

And some of those companies violated industrial dumping permits -- limits that are intended to stem large amounts of chemicals from jeopardizing water quality -- repeatedly and with little to no punishment.

The Times reviewed state, federal and company compliance records and the U.S. EPA's most recent toxic release data, from 2006. Of all the companies operating in the Lake Michigan basin, at least 68 were determined to dump chemicals either into the lake directly or into its many connected or nearby waterways.

Of the 15 highest-dumping companies operating across a four-state area -- Illinois, Indiana, Michigan and Wisconsin -- the investigation revealed:

-- seven Indiana facilities operating in the Calumet Region that surpassed government limits on chemical releases into the waterways between 2002 and 2007.

-- two Wisconsin companies responsible for violations within the same time period.

-- one Wisconsin mill that violated its chemical discharge permit more than 50 times in six years without being punished.

-- only Indiana companies that surpassed chemical discharge limits faced any sanctions or fines by state and federal environmental agencies.

With many of Chicago's major plants from its Southeast Side manufacturing heyday -- U.S. Steel South Works, Wisconsin Steel, Republic/LTV Steel -- having been shuttered in recent decades, Illinois does not have any companies in the top 15. Citgo's Lemont Refinery, off the Des Plaines River southwest of Chicago, is No. 16 on the list.

Of the top 15, officials at the nine companies that exceeded permit limits called their violations rare, while regulators said the violating facilities took corrective measures to ensure problems wouldn't happen again.

But the violations are effective gauges of the companies that are potentially damaging the lake, said Alfred Beeton, former director of the Great Lakes Environmental Research Laboratory of the National Oceanic and Atmospheric Administration.

Under Beeton's rationale, Indiana facilities potentially could be polluting more than other states. All of Indiana's highest-dumping facilities have been cited by the Indiana Department of Environmental Management, some for minor limit deviations.

The tally of breaches among Indiana sites shows strong enforcement, says Bruno Pigott, deputy commissioner for IDEM's Office of Water Quality.

"To me, that means we're doing our jobs," Pigott said. "We take action."

The offenses vary at the nine violating sites. The following is a look at the sites, listed by rank from largest to smallest total discharges to the lake or waterways within its basin:

No. 1: U.S. Steel, Gary Works

The permit for Lake Michigan's largest industrial polluter requires the company to monitor 6,400 variables a month, including chemical and temperature limits. About 99 percent of the time, U.S. Steel officials say, the company is compliant with the variables.

Officials recently reviewed a year's worth of discharge monitoring reports to find the plant operates at an average between 63 percent and 93 percent below its permitted releases of pollutants, such as chromium and suspended solids, the silty residue from wastewater treatment and filtration.

"We feel that is beyond compliance," said Dave Behrens, Northwest Indiana environmental affairs manager for U.S. Steel.

But officials admit 99 percent compliant isn't perfect.

The levels by which the steelmaker has exceeded various limits in recent years range widely.

For example, the company surpassed its limit of CBOD -- the amount of oxygen used, usually measured within five days, to break down carbon-based matter in water -- by 13 percent in 2003. But it skyrocketed past its daily suspended solids cap in February 2005, by 449 percent.

Generally, a high CBOD or BOD -- biological oxygen demand -- means more oxygen is used to break down material, depleting the available oxygen for a waterway's fish or other aquatic life, wastewater experts say.

Low or no oxygen also degrades water's appearance, according to the U.S. Department of Interior's Advisory Committee on Water Information.

In recent years, the steelmaker has received at least four violation letters from the Indiana Department of Environmental Management; it's the first step in IDEM's compliance process. Almost all of the letters referred violations to IDEM's enforcement division, meaning the agency could decide to seek penalties against the company.

Most violation letters don't go to enforcement, so the agency had deemed at least some of the mill's infractions serious enough to pursue penalties, IDEM's Pigott said.

One of the plant's worst recent compliance years was 2005, when it exceeded permit limits 13 times. Violations dwindled to seven in 2007, according to U.S. Steel records.

The company was fined a total of $23,800 for violations during a three-year span beginning in March 2002. Among the misdeeds listed in its 2006 agreed order with IDEM, U.S. Steel unlawfully discharged a combined total of at least 14 gallons of oil and diesel fuel into the Grand Calumet River and exceeded its permitted discharge limits of six chemicals on multiple occasions.

In their response to IDEM, officials at U.S. Steel said they took measures to allay each of the excess discharges and spills, including using absorbent tools to soak up contaminants.

No. 2: Georgia-Pacific, Green Bay, Wis.

Regulators from the U.S. EPA and the Wisconsin Department of Natural Resources say the large paper mill has not violated its wastewater permit in recent years. EPA data show Georgia Pacific discharged 950,000 pounds of nitrate compounds in 2006, almost 95 percent of the nitrates volume discharged by U.S. Steel.

No. 3: U.S. Steel Midwest Plant, Portage

The eastern arm of U.S. Steel's local production operation is the hot rolled coil finishing plant in Portage.

The plant has received at least three IDEM violation letters in recent years, one noting potential problems but not observable infractions.

The Portage plant has surpassed its limits a handful of times in recent years, typically by slight margins.

According to a 2005 report by the Indiana Water Environment Association, the Portage site repeatedly breached its permit limits before an agreed order with IDEM prompted the plant to better prevent violations in 2002.

The plant exceeded its iron discharge limits five times between May 2003 and 2004 by a total of 29 pounds. In response to IDEM, the company detailed its improvements, including repairs to outdated sewer piping, to correct infractions of iron and pH, or the level of the water's acidity.

In October 2005, U.S. Steel closed out an agreed order entered with IDEM from when the plant was owned by National Steel. It paid civil and stipulated penalties totaling $255,100 for unlawful oil discharges and numerous violations of cyanide, iron and chromium discharges.

No. 4: NewPage, Kimberly, Wis.

Regulators from the U.S. EPA and the Wisconsin Department of Natural Resources say the plant, which produces magazine paper, has not violated its wastewater permit in recent years.

No. 5: Verso Paper, Quinnesec, Mich.

Regulators from the U.S. EPA and the Michigan Department of Environmental Quality say the mill, which makes coated freesheet paper, has not violated its wastewater permit in recent years.

No. 6: ArcelorMittal, Burns Harbor

An analysis of ArcelorMittal's three largest Northwest Indiana sites shows all of them have had trouble in recent years complying with certain permit rules.

The Burns Harbor steel-making site has received at least three IDEM violation letters since June 2004.

In 2005, the Burns Harbor and East Chicago sites were sold from ISG to Mittal Steel.

Most of the plant's problems have involved meeting discharge levels of suspended solids, oil and grease, plus wastewater temperature.

In letters sent to IDEM alerting the agency of its excess discharges, the company blamed many cases on laboratory or sampling errors and not actual violations. For example, the plant blew past its daily oil and grease limits in June 2006 by more than 4,600 pounds to 10,695 pounds, but the company referred to the sample tested as "compromised."

The plant also committed several unlawful bypasses, wherein wastewater -- at times only partially treated -- passes through directly to the ground or waterways without full processing or cleaning.

The site entered an agreed order with IDEM in December 2006 for infractions dating back to when it was owned by ISG in 2003. Among the problems were bypasses and chemical exceedances and for mischaracterizing temperature violations in the company's reporting as being allowable.

The company closed out the agreement in March last year, paying a $24,000 civil penalty.

In the months following, the plant continued to sporadically surpass some limits, including its daily oil and grease cap again in January.

No. 7: Foremost Farms, Chilton, Wis.

Compliance records from the Wisconsin Department of Natural Resources show Foremost Farms violated its permit at least 53 times in five years, once exceeding a chemical limit by almost 1,200 percent.

Between 2002 and fall 2007, the company exceeded its permitted caps of ammonia, suspended solids and zinc, an element that does not dissolve in water.

Jim Wittenberger, Foremost regulatory compliance manager, argued the site does not have a problem staying compliant.

"You might have an upset condition (at the plant) for a few days," Wittenberger said, referring to a sudden change in treatment that may result in violations and degraded water quality. "You have an exceedance, but you're able to correct it."

Wittenberger said the cheese plant deals in much smaller quantities than larger industrial facilities. Its highest discharge of suspended solids during any violation was 202 pounds in 2002. To contrast, U.S. Steel's Gary plant is allowed to dump almost 19,000 pounds of solids a day.

Part of its wastewater discharge permit granted by the Wisconsin Department of Natural Resources details the plant's compliance history as spotty, citing its "several limit exceedances." It also states, though, that "the facility is getting better and is expected to improve."

"We don't have major issues," Wittenberger said. "But we do have these burps."

The facility has had at least two "burps" of some chemical every year since 2002. Among them was a discharge of 1,670 pounds, or 1,175 percent, over its limit of zinc in June last year.

But the plant hasn't faced any fines for its infractions.

Wisconsin regulators sent notices of noncompliance -- the agency's first step in regulating -- for Foremost's violations through 2006, and the plant corrected any issues, said Michael Reif, wastewater compliance specialist for the Wisconsin Department of Natural Resources.

About 90 percent of cases are resolved with a facility's response to a noncompliance letter, according to Wisconsin regulators.

Reif called Foremost a responsible company.

"I don't get complaints about Foremost," he said. "I think that's important to them."

If the company were a habitual violator, there would be consequences, Foremost spokeswoman Joan Behr said.

"We wouldn't be able to stay in business," Behr said.

No. 8: Cargill, Hammond

Sweetener and starch producer Cargill discharges its treated wastewater through a single outfall into Lake Michigan.

Cargill denied The Times access to its Hammond plant but answered questions through e-mail. Spokesman Bill Brady called the company's compliance record "excellent."

"We would put our record up against anybody's," Brady said in an e-mail. "We have paid nothing on water-related issues in at least the last 10 years."

Though it has paid nothing, regulators say the company has violated its permit limits, most recently in the spring of last year.

Cargill exceeded its chlorine limits by as much as 83 percent at that time, said James Coleman, of the Water Enforcement and Compliance Assurance Branch of the U.S. Environmental Protection Agency.

The plant has received at least three violation letters from IDEM stemming from 2004. IDEM records show the company violated its pH limits five times in 2003, by no more than 17 percent each time.

After receiving a poor inspection report and violation letter for exceeding its pH caps in August 2004, Cargill instituted pH quality-control measures at the plant, IDEM records show. The company also fired one employee, reprimanded another and re-trained operators on pH limits and reporting requirements.

Subsequent compliance records Cargill reported to IDEM show fewer pH infractions, but violations of suspended solids and BOD5, the amount of oxygen, measured in more than five days, used to reduce water-based matter. A December 2005 IDEM inspection showed Cargill exceeded its daily solids limit, by 41 percent to 10,808 pounds, and its BOD5 limit, by 43 percent to 11,368 pounds.

Cargill, which previously had notified IDEM of both violations, responded to regulator concerns, and IDEM records indicate no further action was taken.

No. 9: ArcelorMittal, East Chicago (West)

ArcelorMittal's Dickey Road plant received three EPA compliance administrative orders between 2003 and 2006 for violations, including unauthorized oil and grease discharges. The orders did not go to court and were settled through corrective actions at the plant.

The company was ordered to take corrective measures, costing a combined $1.56 million.

EPA officials say the agency settles most of its enforcement actions in such a way. Any penalties paid are part of a settlement and don't necessarily reflect an admission of guilt.

The plant also has received at least three IDEM violation letters from the state in recent years for breaking zinc limits and for visible oil sheens on waterways at the site.

Operating under ISG Indiana Harbor Inc., the site had six limit exceedances in 2003 for oil and grease, pH and suspended solids, in part prompting an agreed order with IDEM for violations. IDEM closed out the agreed order in September 2006 after the company paid a $20,000 civil fine.

An IDEM site inspection in December 2004 said the company had accomplished "a considerable amount of work" in cleaning an intake area once glazed with an oily sheen.

No. 10: ArcelorMittal, East Chicago (East)

IDEM records show ArcelorMittal's other East Chicago site has struggled more with unpermitted discharges than with limits on certain chemical releases.

The plant unlawfully has bypassed wastewater at least 13 times since July 2003, at one point discharging 379,000 gallons of treated water in less than an hour because of a power failure, IDEM documents reveal.

In the last five years, the site has received at least three IDEM violation letters for exceeding limits of zinc and other elements. Operating as Ispat Inland in November 2004, the site entered an agreed order with IDEM for multiple bypasses and releases of oil and other materials.

ArcelorMittal closed out the order in January last year, paying a $25,500 civil fine and building a new pump station to help halt bypasses there.

The site also appears to have periodic problems controlling the acidity of its wastewater. Both ArcelorMittal and Ispat Inland Inc. notified IDEM of at least eight incidents in recent years in which the plant had violated its acidity, or pH, limits.

ArcelorMittal later argued the cases may have been wrongly labeled as violations in confusion stemming from the plant's overdue permit renewal.

In a November 2007 letter to IDEM, the company stated that the pH incidents might not be illegal given language in the plant's 1984 permit that allowed such breaches of the limit under certain circumstances.

"However, the current administratively extended permit issued in 1996 is silent on the citation," ArcelorMittal environmental manager James Flannery wrote, meaning it did not properly address allowable pH exceedances.

IDEM has administratively extended several major permits instead of issuing new ones that would include updated water quality standards.

ArcelorMittal requested the incidents be removed from its violation record and said the pH problem's "root cause has been found and controlled."

No. 11: Menominee Paper Co., Menominee, Mich.

Regulators from the U.S. EPA and the Michigan Department of Environmental Quality say the paper mill has not violated its wastewater permit in recent years.

No. 12: NewPage, Escanaba, Mich.

Regulators from the U.S. EPA and the Michigan Department of Environmental Quality say the plant, which produces about 770,000 tons of paper a year, has not violated its wastewater permit in recent years.

No. 13: Thilmany, Kaukauna, Wis.

The Thilmany paper mill violated its permit limits six times in recent years, and it has been sent two notices of noncompliance and given one verbal notice, regulator records show.

Half of the violations took place in 2003 and involved breaches of daily limits of suspended solids. In one of the incidents, the company blew past its 21,720-pound limit by 6,048 pounds.

Thilmany has not faced any fines in recent years for its permit infractions. Officials at the mill usually explain away any incidents and implement measures to fix problems, said Mark Corbett, engineer with the Wisconsin Department of Natural Resources.

No. 14: Packaging Corp. of America, Filer City, Mich.

Regulators from the U.S. EPA and the Michigan Department of Environmental Quality say the containerboard-making mill has not violated its wastewater permit in recent years.

No. 15: BP Refinery, Whiting

Records from IDEM and BP show the country's fourth-largest oil refinery has wafted in and out of permit compliance in recent years pertaining to water discharges.

A February 2003 IDEM inspection report stated, "Overall the facility does a good job of treating the wastewater generated at the facility."

But the same inspection said compliance challenges exist, including brown discoloration of discharged water, and sludge buildup on a treatment tank that separates solid matter from water and is later removed.

The refinery has exceeded its monthly average limits of ammonia and suspended solids more often than its daily guidelines.

BP-provided data show the refinery has violated its monthly limit of solids discharges at least 25 times since the end of 2003, but its overall solids discharges have declined on average since then.

When BP has broken its daily cap on suspended solids -- at least six times since November 2002 -- it has at times been by large amounts.

For example, problems processing water at the plant in January 2003 contributed to an exceedance of suspended solids by 29,726 pounds. Other sporadic overflows of solids have ranged in amounts from 152 pounds to 2,062 pounds.

"Day in, day out, we're never that close to our permit limits," said David Moye, head of accountability at BP's lakefront wastewater treatment plant. "It's not like we're just riding right below them every day."

For its scattered infractions, BP has received few notices from IDEM, getting at least two violation letters in September 2004 and February 2007.

The 2007 letter addressed an unsatisfactory December 2006 IDEM inspection, citing poor sludge disposal, marginal record keeping and two solids violations.

In both cases, per IDEM's request, BP sent the agency explanations for the incidents and details on steps to fix problems, including upgrading filters and reducing water flow at some tanks.

IDEM called BP's response to the September 2004 letter "adequate" and said it looked forward to the refinery's "continued compliance."

IDEM and BP records show few daily ammonia infractions in recent years.

"We overachieve quite a bit when it comes to ammonia," said Steve Warzyniak, a BP engineer charged with daily compliance oversight.