A confidential city report shows councillors have known since January that 24 billion litres of untreated sewage escaped undetected over a four-year period from a massive sewer overflow tank into Chedoke Creek, which runs along Highway 403 into Cootes Paradise.

The watery sewage — enough to fill 10,000 Olympic-sized swimming pools, or an area of 12 square kilometres to a depth of two metres — seeped out of the tank because a gate had been left partially open for more than four years.

The confidential report to council on Jan. 16, along with a second one on Sept. 4, show city staff have been recommending that details of the spill be kept secret from the public as long as possible because of potential legal action the city could face.

The two reports, obtained by The Hamilton Spectator, state Ontario's environment ministry is investigating the massive spill, which could lead to charges.

"Given the significance of this discharge event, both in terms of the volume, duration and impact, staff anticipate that the (ministry's) investigation into this matter may result in charges being laid against the City of Hamilton and possibly certain employees," according to the Sept. 4 confidential report.

The January report states the ministry's investigation had already led to a number of interviews of city staff and contractors.

The reports state the city could face a maximum fine up to $6 million for the incident. It's also estimated to cost $2 million to remediate the creek.

Neither the remediation work or any fine levied would be covered by the city's insurance, according to the reports.

The Spectator informed the city it had obtained two confidential reports and submitted a number of questions Wednesday morning to councillor Lloyd Ferguson, chair of the public works committee. Late Wednesday morning, council went in camera to discuss The Spectator's questions.

Several councillors, including Ferguson, declined to comment when they emerged from the in-camera session.

About an hour later, in response to The Spectator's questions, the city put out a press release acknowledging publicly for the first time that approximately 24 billion litres of watery sewage had been discharged because a gate at the King Street West tank had been left partially open for 4.5 years.

"Hamilton city council takes this matter very seriously and today is sharing additional information that has become available based on the city's investigations," the press release stated.

The waste water overflow pipe that dumps into Chedoke Creek and then runs into Cootes Paradise. | Cathie Coward/The Hamilton Spectator

Lynda Lukasik, executive director of Environment Hamilton, said the long-standing discharge from the overflow tank "is shocking."

"That's a brutal impact on Cootes Paradise and Hamilton Harbour," said Lukasik. "Those (overflow) tanks are just a Band-Aid solution."

"The City of Hamilton better have a good plan going forward to make sure it doesn't happen again," she added.

The two confidential reports were prepared jointly by the city's public works department and the legal and risk management services division of the corporate services department.

The reports state the city was unaware that a bypass gate at the King Street West overflow tank across from the Cathedral of Christ the King had been left partially open from Jan. 28, 2014, until July 18, 2018, allowing untreated sewage to flow into the creek for 1,633 days.

During heavy rainfall, a combined sewer overflow tank captures a mix of rainwater and sewage that would previously have flowed untreated into Cootes Paradise, the harbour or the lake. Once the wet weather subsides, the overflow can be pumped from the tank to the main sewage treatment plant at Woodward Avenue.

The King Street West overflow tank can hold 77 million litres of watery sewage.

The problem came to light after a second failure involving a different gate occurred in January 2018, which increased the amount of discharge into Chedoke Creek.

When the 2018 failure was being investigated, it was discovered the first gate had been left about five per cent open since January 2014.

"To date, staff have not been able to determine why the gate was opened or by whom," the Sept. 4 report states. "The automated monitoring systems at the tank did not detect the discharge, nor was the discharge visible to staff during monthly facility inspections."

The gate was fully closed on July 18, 2018, and a day later it was confirmed by staff that there was no further discharge into the creek.

Locks on a gate near the area where pipes flow from the waste water tank at Cathedral Park into the creek at the foot of Glen Road.| Cathie Coward/The Hamilton Spectator

About 30 per cent of the total discharge, roughly 7.2 billion litres, occurred between January and July 2018, when the two gates were improperly open at the same time.

After the discharge was discovered, more than 242,000 litres of material were removed from the surface of the creek and taken to the Woodward Avenue plant for treatment. That amount represents about 1/100,000th of the total discharged over the 4.5-year period.

Dan McKinnon, the city's general manager of public works, said the total discharge amounted to about four per cent of the annual flow through Hamilton's wastewater treatment plants.

"If you want to quote me, one litre is too much," said McKinnon. "Hamilton Water and the public works folks here exist for the purpose of making sure nothing gets into the environment.

"From a personal perspective, this happened when I was the senior director in Hamilton Water so this happened on my watch," said McKinnon. "It is absolutely heartbreaking for me and it's heartbreaking for our staff.

"This kind of news for the community, they're just going to shake their head," he added. "It's going to challenge their trust and confidence in us and all we can do is work our ass off to try to bring that back."

McKinnon said the city made the decision to not provide information about the discharge once the matter was under investigation by the environment ministry.

"We're aware that the investigation is ongoing and that's why we're not saying anything about it," he said.

McKinnon said the city is still trying to determine how and why the gate was left open for years.

"Right now, we've got our theory of what happened but it's not with 100 per cent certainty," he said.

In the January confidential report, councillors were informed reports from a consultant hired by the city to examine the spill had to be turned over to the ministry by the end of January and the contents of the report "may become public."

"City staff recommend that the consultant reports remain confidential to the extent possible until such time as the disclosure of the entire reports become necessary, either in the course of the (ministry's) involvement or by applicable law," the report states, "in order to protect the city's ability to defend against possible regulatory charges."

The September report also notes "premature release" of the consultant reports could increase the city's "exposure to potential private prosecutions or class actions."

Pipes from the waste water tank run under the 403 to Chedoke Creek which flows into Cootes Paradise. | Cathie Coward/The Hamilton Spectator

The two confidential reports note staff decided to withhold a public statement about the spill on the advice of an external lawyer with environmental expertise who has been retained by the city.

The Sept. 4 report notes the city has prepared a communications plan and "Issues Management note capturing key messages and potential Q&As."

"The (ministry's) investigation and accompanying orders, while not confidential, have not been covered in the media or shared publicly by the (ministry) or the city to date," according to the Sept. 4 report.

"Staff recommend that for the current time, that a proactive media release not be made but instead that a temporary holding statement (or parts of it) be used in response to any incoming media inquiries," according to the Sept. 4 report.

In the sample statements that followed, there is no mention of the fact 24 billion litres of untreated sewage escaped undetected, that a gate was left partially open for more than four years, and that the city could be facing charges and a potentially stiff penalty.

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Instead, the suggested talking points state:

• The city discovered a discharge was occurring on July 18, 2018, immediately stopped the discharge and began cleanup activities in the Chedoke Creek area;

• The city continues to work with the ministry in reviewing the incident to understand how and why the spill occurred;

• The city continues to monitor water quality in the impacted area and "monitoring showed substantial improvements in water quality conditions, within weeks of stopping the discharge and odours also dissipated quite quickly."

When the discharge was discovered on July 18, 2018, the city reported it to the environment ministry's Spills Action Centre. Two weeks later, the environment ministry issued an order against the city requiring certain actions to be taken with specific deadlines.

The city was required, among other things, to:

• Bring in an external expert to evaluate the spill's impacts and provide a plan for mitigating the damage and remediating the creek;

• Inspect critical valves and control points for all sewer overflow tanks in the city;

• Review and revise as necessary the city's spills procedures.

The September report states the city has complied with all of the ministry's requirements.

The city also noted no similar issues were detected at other overflow tanks.

It's not clear from the reports what environmental impact the discharge has had on plants and animals in the creek and Cootes Paradise.

A remediation report prepared by the consultant recommends hydraulic dredging of the creek bed to remove some of the organic material.

The Spectator filed a Freedom of Information request earlier this year to obtain the consultant's reports but the request was denied by the environment ministry.

The ministry indicated in response to questions from The Spectator that a second compliance order was issued to the city last week requiring clarification and confirmation of the impacts of the spill, as well as recommendations for remediation, mitigation and monitoring.

Asked why the amount of discharge and the 4.5-year time period hadn't been disclosed publicly, the ministry stated it exchanged information with the Hamilton Conservation Authority and the city's public health unit.

"As the matter has been forwarded to the ministry's Investigations and Enforcement Branch, it would be inappropriate to provide any additional comment," the ministry stated.

The confidential September report also notes the city has obtained legal advice about a potential issue of non-compliance related to one of the conditions contained in the certificate of approval issued by the ministry for the King Street West overflow tank.

Under one of the certificate's conditions, the city was required to conduct routine sampling at the overflow tank but the sampling equipment had been experiencing problems since at least 2012 and the sampling didn't occur.

New sampling equipment was installed but the September report states the equipment is still not functioning properly.

If the city is charged and found guilty for infractions related to the overflow tank, it won't be the first time Hamilton has been punished for environmental wrongdoing.

In 2000, the city was fined a total of $450,000 after pleading guilty to two charges of allowing toxic liquid to seep from the old Rennie Street dump into Red Hill Creek and then Hamilton Harbour.

sbuist@thespec.com

905-526-3226

- Hamilton kept sewage spill details secret from the agency responsible for Cootes Paradise