Concrete Capture

[Here are Part 1 and Part 2 of this three-part series]

Cover photo: Cement kiln dust (CKD) storage at Lafarge Brookfield. According to CABOT member Lydia Sorflaten, from 1965 to 1994, the CKD was landfilled behind the plant without any containment measures in place. A barrier several metres high was later constructed around the perimeter to contain the material. Today not all CKD is landfilled on site — some is sold as a soil amendment and spread on farm fields. Photo courtesy Lydia Sorflaten

In 2019, as part of the Industrial Approval issued to Lafarge to burn scrap tires at its Brookfield plant, Nova Scotia Environment (NSE) required that the company test the cement kiln dust (CKD) prior to tires being added to the fuel mix, and every month while tires were included.  

CKD is a fine, powdery, waste product that is removed from the exhaust gas coming out of the kiln by the electrostatic precipitator (ESP), the pollution abatement unit first installed at the plant in 1966. Some of the collected particulate is returned to the kiln or added to the cement grinding mill, but the rest ends up either being “stored” or sold. Lafarge produces more than 10,000 tonnes of CKD every year, and vast stockpiles of it occupy several acres at the Brookfield site. 

According to its Environmental Assessment (EA) registration document, Lafarge didn’t expect there’d be any changes to the quantity or quality of CKD with the use of scrap tires, something it said would be “confirmed through the demonstration program.” 

In the late summer of 2019 when Lafarge hired ALS Global to test the CKD, the analysis revealed that all six samples exceeded the detection limit for N-nitrosodimethylamine (NDMA) — a potent human carcinogen that is believed to pose a significant risk to human health even in small concentrations.  

It wasn’t the first time an analysis indicated the CKD might be hazardous. In Part 2 of this series, the Halifax Examiner reported that when Nova Scotia Environment (NSE) officials collected samples of the CKD from Lafarge’s landfill in 2007, the analysis found the “material not appropriate for disposal in a municipal landfill.” 

But according to the company, what’s landfilled on site only represents the unsold product. The rest of the “limestone derivative” is sold for use in various fertilizer products, which eventually make their way onto farm fields in the province. 

‘NDMA is definitely there’

Earlier in this series you were introduced to Douglas Hallett, an internationally renowned toxicologist of more than 40 years. He was retained as an expert witness in the 2007 environmental review tribunal when Lafarge’s plan to burn alternative fuels, including scrap tires, at its Bath plant in southern Ontario was challenged by local environmentalists including Gordon Downey of the Tragically Hip. 

Hallett’s expertise was also sought here in Nova Scotia, when the Citizens Against the Burning of Tires (CABOT) — many of them residents who live near the Brookfield plant — requested that new information from Hallett be admitted as part of the evidence in a judicial review of the minister’s 2017 decision to approve the TDF plan. The group argued the minister’s decision should be re-visited because the tire-burning proposal was ill-advised, not based in any science, and hazardous to nearby residents and the environment. But as previously stated, Hallett’s offer to provide a report that would “fully consider” the outstanding issues was denied by the court. 

In her decision, Justice Denise Boudreau said, “the admission of such evidence would be, in my view, an inappropriate distraction.”

But one of the important questions raised in Hallett’s 2017 affidavit zeroed in on the “ash residuals,” or CKD. How might its composition change with the addition of tires? 

“There is a real and substantial risk that groundwater may become a contaminated source of drinking water if the ash residuals contain [N-nitrosodimethylamine] NDMA and products of incomplete combustion of tires,” wrotes Hallett, who pointed to the spectacular way in which this occurred in areas of Ontario from both the manufacturing of chemicals and synthetic rubber for tires, as well as from the Hagersville tire fire, when 10 million tires burned for 17 days.

Little did Hallett know, NDMA was already present in the CKD — even before scrap tires were included in the fuel mix.  

When the Examiner asked the Nova Scotia Department of Environment (NSE) about the 2019 analysis that showed the presence of NDMA in all six samples of CKD — at twice the detection limit in five of them — spokesperson Barbara MacLean provided this response:  

NDMA (or N-nitrosodimethylamine) is no longer used in production processes, but it can be an unintended by-product of municipal and industrial processes. In this case, Lafarge is monitoring the Cement Kiln Dust (CKD) which is a waste generated as a result of the production of Portland cement. The U.S. Environmental Protection Agency (USEPA) has both residential and industrial screening levels, that when exceeded would warrant further investigation. The analysis from the Lafarge CKD samples indicated maximum concentrations that fell well below the USEPA residential screening level. In addition, Health Canada has a maximum allowable concentration for NDMA in drinking water. Analysis of surface and groundwater samples at the facility in 2019 found all groundwater results were below detection limits and surface water concentrations, were all well below the Health Canada drinking water limit.

To try to make some sense of this, the Halifax Examiner reached out to Hallett and sent him a copy of the CKD analysis. 

Over the years Hallett has developed an impeccable reputation internationally as a leading expert in dioxins and PCBs. His bio states that he was “well known to Dow, Occidental, Uniroyal, Texaco, Exxon, Monsanto, and most pulp and paper manufacturers.” He has been called to testify in hundreds of court cases involving contamination events or toxic exposures.

Hallet also has extensive experience with NDMA, beginning with his PhD work dating back to the mid-1970s, to his work involving the Hagersville tire fire, and his involvement in the water contamination issue that has plagued a small southern Ontario town for decades.

In 1989 his company, Eco Logic, was called in to assist in the analysis of drinking water for the Region of Waterloo in Ontario when Elmira’s aquifer was found to be contaminated with high levels of NDMA. Nearly 32 years later, the residents still can’t drink the water. ^[1]In 1989 when NDMA was found in two well fields in Elmira, the wells were closed and extensive sampling of municipal and private wells began. In 1991 NDMA was found at a concentration of 0.019 parts … Continue reading

With regards to the NDMA analysis done on Lafarge’s CKD, Hallett says, “All of the samples are positive for NDMA well above the detection limit…This means that NDMA is definitely there…and what you’ve got is one of the most powerful carcinogens ever found.” 

According to NSE, the detection limit “is the lowest concentration of a parameter that a laboratory is able to accurately detect and report with confidence…In most cases, the detection limit is significantly below any level that would be of concern.”

But is it below a level that would be of concern in this case? For what it’s worth, in 1991, when it was decided that a pipeline would be built to bring drinking water to the town of Elmira from Waterloo, the concentration of NDMA in the drinking water was 0.019 ppb. The concentration of NDMA in one of the CKD samples was nearly eight times higher than this. Today, the NDMA standard in Ontario for drinking water is 0.009 ppb, which appears to be much lower than the levels detected in all six of the CKD samples. ^[2]The unit used in Lafarge’s CKD analysis was nanogram/gram (ng/g): 1 ng/g is equivalent to 1 part per billion (ppb). Of the six CKD samples, the highest concentration of NDMA was 0.147 ng/g or 0.147 … Continue reading

Asked about the sale of CKD as an agricultural amendment in the province, NSE spokesperson Barbara MacLean replied: “Nova Scotia Environment does not regulate the use of cement kiln dust as an agricultural soil amendment, you’d need to contact the Canadian Food Inspection Agency (CFIA) or Lafarge to ask this question.”

So I did both. 

Robert Cumming, Lafarge’s director of environment and public affairs downplayed the presence of NDMA in the CKD samples: “The detection limit [for NDMA] is only the limit at which the lab was able to detect the compound at less than parts per billion levels and this is not related to a compliance limit.” 

“The CKD is composed of finely ground natural limestone, quarried on the site, which is removed from the dust captured by the ESP.”

While Cumming seems to play down any potential harms associated with CKD, the company publishes this safety datasheet, which paints a very different picture of the material, stating the product can cause severe skin burns, eye damage, respiratory irritation, damage to organs, and cancer (if inhaled). It can also be harmful to aquatic life. 

“Avoid release to the environment,” reads the safety datasheet.

The datasheet raises concerns regarding whether the CKD poses any occupational health risk to employees of the cement plant, or whether it could be in leachate or runoff from the site. As well, since it has been detected in the CKD, could it also be in the particulate matter emitted from the main stack, particularly during incomplete combustion or during upset conditions, which means nearby residents could be inhaling it?

As previously mentioned, Lafarge currently sells CKD as a limestone derivative, approved by the Canadian Food Inspection Agency (CFIA) for its use in fertilizer products. 

Since 2008, a patented technology called N-Viro has been used at a Walker Industries facility located in Aerotech Park near the Halifax Airport to process Halifax’s sewage sludge — or biosolids — and turn it into fertilizer. In the process, cement kiln dust (CKD) is added to the dewatered sludge, as what’s called an “alkaline admixture.” The resulting product is spread on Nova Scotia farm fields, a practice that has raised the ire of many in the province, who are concerned that human sludge contains heavy metals, pharmaceutical residues, and other emerging substances of concern.

The Examiner contacted the CFIA to find out more about how it approves CKD use in fertilizers and whether it does any independent testing of CKD and for what compounds. 

According to a media spokesperson with the CFIA, cement kiln dust is exempt from registration under the Fertilizers Act and Fertilizers Regulations, because it meets the definition of calcitic limestone on the List of Primary Fertilizer and Supplement Materials. Before being placed on this list, the CKD undergoes a “one-time risk assessment based on publicly available data and published scientific literature.” ^[3]The CFIAs assessment process includes: 1. Hazard identification — characterization of innate adverse toxic effects of agents. 2. Dose-response assessment — characterization of the relation … Continue reading

A group of scientists from different disciplines review the data and make decisions about exemption eligibility based on risks to human, plant, animal health, and the environment. “If new risk evidence comes to light a material can also be removed from the List as no longer eligible for exemption,” said the spokesperson.

Currently the CFIA only administers safety standards for 11 metals of concern. ^[4]Arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb), mercury (Hg), molybdenum (Mo), nickel (Ni), selenium (Se), and zinc (Zn)), as well as upper limits for dioxins and … Continue reading In addition to the standard suite of metal analysis and dioxin and furan testing, CKD products are analyzed for levels of thallium and vanadium. The CFIA currently does not have a standard for NDMA.

Products that are exempt, like CKD, can be imported or sold in Canada “without CFIA-pre-approval and a safety assessment each time, based on the general low-risk profile of the product.” 

When it comes to NDMA: 

“The CFIA is aware of NDMA being a potential byproduct of the manufacturing process of CKD. However, according to the published scientific literature, NDMA has not been identified as a contaminant of significant concern in CKD due to its low prevalence and concentrations.” 

Asked to specifically comment on the presence of NDMA in CKD from the Lafarge plant, the CFIA media spokesperson replied, “It is difficult to comment on specific cases without knowing the detection limit and the type of analysis used.” The spokesperson suggested I send the NDMA analysis to their attention as a “complaint” through the Pre-market Application Submissions Office, and if deemed appropriate, the matter would be investigated. ^[5]Further to sending in a “complaint” to the CFIA: “The complaint should identify your concern and be accompanied by as much information as possible to facilitate the CFIA’s taking action, … Continue reading

 The Examiner is currently engaged in this process. 

The Examiner also sent the NDMA analysis of Lafarge’s CKD to Environment and Climate Change Canada (ECCC). According to its media spokesperson, at the federal level the Prohibition of Certain Toxic Substances Regulations prohibits the manufacture, use, sale, offer for sale, or import of NDMA, with a limited number of exemptions. NDMA is currently considered a toxic substance in Canada. 

The obvious follow up question was this: “The sale of NDMA is prohibited. However, the analysis showed that NDMA is present in the CKD, which is being sold as a soil amendment. If the CKD contains NDMA, would this not prohibit the sale of the CKD?”

ECCC replied: “If the cement kiln dust contains NDMA, its sale would be prohibited.”

According to the ECCC, its mandate is to administer and enforce environmental laws in Canada, including the Canadian Environmental Protection Act (CEPA) and the aforementioned Prohibition of Certain Toxic Substances Regulations. When there’s sufficient evidence there’s been an offence “enforcement officers may take appropriate action” by issuing warnings, environmental compliance orders, or directions. “When appropriate, officers conduct investigations to collect evidence for the purposes of prosecution in a court of law.”

As a result of efforts by the Examiner to bring the NDMA contamination of CKD to the attention of ECCC, the matter is currently under investigation. 

According to ECCC spokesperson, Chelsea Steacy, the department is now reviewing the Lafarge CKD file “to verify compliance” with the CEPA and related regulations. 

“We are not able to comment on the details of active enforcement matters.”

Green-washing cement 

As previously stated, Lafarge claims tire derived fuel (TDF) has the “potential” to lower its greenhouse gas emissions by 30% for every tonne of coal replaced. 

But how exactly did the cement manufacturer come up with that figure?

According to Jessica Assaf, Lafarge’s manager of corporate communications in eastern Canada, it has a lot to do with what’s called biogenic carbon — the natural rubber in tires, which is considered carbon neutral by the Intergovernmental Panel on Climate Change (IPCC). Assaf says biogenic fractions in scrap tires is 15-30%. According to the US Tire Manufacturer’s Association, it’s about 19%. 

“Lafarge is required to test for biogenic carbon in the scrap tires used at the plant and to report third party validated plant emissions to Nova Scotia Environment for their review and approval,” says Assaf.

Assaf says the predicted emission reductions are also based on the chemistry of scrap tires compared to coal, so from a pure chemistry perspective, you can also expect a 10% reduction per tonne of coal replaced.

Earlier in this series you were introduced to Mark Gibson, a former associate professor in the Department of Civil and Resource Engineering at Dalhousie University.  According to Gibson, between the biogenic carbon and the lower carbon emissions of tires compare to coal-petcoke, the 30% reduction is a “correct approximation” which he confirms is validated annually by third party auditors when Lafarge produces its annual greenhouse gas report. 

But is natural rubber really carbon neutral? 

Basically the rationale is that natural rubber is a sustainable source of carbon because when new rubber trees grow they will sequester or store up as much carbon as was released to the atmosphere when the rubber was burned.

It’s the same justification that’s used for biomass (chipped trees) and is reflected in the highly flawed emissions accounting systems of international climate agreements. ^[6]The Kyoto accounting system is recognized as being deeply flawed because it was based on production-based accounting rather on consumption-based accounting, which means that countries are responsible … Continue reading

But many argue that while this accounting has made its way into most national or regional regulations or standards that define renewable energy sources, the assumption is veering on delusional. 

The Examiner has covered the flawed assumptions associated with biomass and carbon neutrality here, here, and here. The same scrutiny should be applied to “alternative fuels” like scrap tires. 

For instance, where does this natural rubber come from? According to various news reports and studies on the subject, growing rubber trees isn’t benign. One 2015 study reported that in just one decade, more than two million hectares of natural forests or farms had been converted into rubber plantations — the biggest impact being felt in southeast Asia. The study authors estimated that given the projected demand for rubber, that by 2024 an additional 4.3 to 8.5 million ha would be required. The conversion of forests to monoculture rubber plantations not only takes a toll on biodiversity, but the pesticides and sediment runoff is causing other deleterious downstream effects. 

It also has implications for GHG emissions.

When natural forests are converted to rubber plantations, carbon dioxide is released into the atmosphere. However, claims of natural rubber being carbon neutral ignore this. Also missing from the equation is the amount of carbon lost to the atmosphere from the disturbed soils when forests are being converted rubber tree farms. Carbon in forest soils have been there for hundreds if not thousands of years and clearcutting unlocks it, and releases it to the atmosphere. 

A carbon accounting method that sets GHG emissions from burning natural rubber in a passenger tire at zero has been recognized as a methodological mistake by the Scientific Committee of the European Environment Agency, as well as other prominent scientists. Despite this, it’s the kind of thinking that now dominates renewable energy production in all OECD countries. 

Add to this the fact that burning these materials can turn out to be much cheaper for industries — maybe even a money maker when it comes to burning scrap tires — and can often be done without changing too much of the existing infrastructure. For cement manufacturers, that’s a win-win. They can increase production and claim, on paper, to be reducing GHG emissions simultaneously. 

Sounds a lot like shuffling deck chairs to me. 

When it comes to scrap tires, life cycle assessment (LCA) is one way of determining what the most environmentally beneficial alternatives for reuse are. In other words, is it better for the environment to recycle tires or to burn them for energy, say, in a cement plant?

The answer seems to depend on how much you’re willing to take into consideration. 

If you ask Lafarge, it argues that using scrap tires as an alternate fuel source makes the most environmental sense from an emissions standpoint. As we’ve seen, part of this argument stems from the fact that GHG emissions from burning natural rubber are not being counted in GHG accounting systems. ^[7]This 2010 study can be found on Lafarge’s Web site. One of the study authors was employed by Holcim, a Swiss-based building material and aggregate company that merged with Lafarge in 2015 to form … Continue reading

But emissions reductions aren’t the only environmental category to be considered in a life cycle assessment. 

This 2012 study that appeared in The International Journal of Life Cycle Assessment found that when it comes to scrap tires, recycling them provided “greater impact reductions” than burning them as fuel in terms of: energy demand, iron ore consumption, global warming potential, acidification, eutrophication, smog formation, and respiratory effects.

The right to a healthy environment

While we have yet to see what the actual TDF emissions from the stack tests or the air dispersion modelling will reveal, we know that the only way to really assess what people downwind are breathing in is by installing ambient air monitors that at a minimum measure dioxins and furans, fine particulate matter, and volatile organic compounds (VOCs). ^[8]In Part 2 I explained that when GHD was developing air emission estimates for modelling the use of TDF as a fuel source — “to determine the change from existing condition emission rates when … Continue reading

As well, emissions are not only airborne. As we’ve seen, even before scrap tires were being burned, the CKD was shown to contain NDMA as well as other toxic compounds — making it unsuitable for a municipal landfill, but apparently not unsuitable for growing our food in. 

Fred Blois has been involved in CABOT since it began. He lives in Old Barns, as the crow flies about 7 km from the Lafarge plant. “What I’d like to see is for an ambient test site set up near the plant for air pollution and for water pollution, and it shouldn’t be Lafarge monitoring either of those,” he says. 

“People are using the water right out of the lake, and that’s just not right. And because of what’s in the CKD, we shouldn’t be using that in farmers’ fields either. It’s an unknown. What is this doing to the land?”

Blois says that over a decade — between 2007 and 2017 — each and every roadblock to burning tires that citizens managed to put up, was systematically removed so that in the end Lafarge got exactly what it wanted. 

“Our planet is in trouble. Nova Scotia needs an Environmental Bill of Rights and the court to enforce it. We need a court that views problems through an environmental lens and we need political leadership which realizes that anything less would fly in the face of democracy,” he says. 

Over the last several decades, environmental and public health protections have been overridden by the expansion of corporate rights, and extractive and commercial activity. Laws in Canada and elsewhere have evolved in such a way that proposed development (extractive or otherwise) is insulated from community control. A number of legal experts, including David Boyd, Cormac Cullinan, and those at the Community Environmental Legal Defence Fund in the US, agree that the permitting process is flawed because the rules regulating an industry have often been developed by the industry itself. 

We’ve seen in the case of Lafarge, for instance, how emissions are self-reported, and how there are really no legally binding guidelines for air pollution, only voluntary guidelines. Nothing is legally enforced. 

Industry has been given a free ride, only we’re paying for it. 

Blois is right. We need an environmental bill of rights, one that protects the environment by granting humans the right to a healthy one.