Summary of public comments received on the draft screening assessment report and risk management scope for coal tars and their distillates

To improve understanding, we have provided a description of the “Substance Identity” of coal tar-based pavement sealant.

The screening assessment report (SAR) was updated to reflect this information. 

Please consider the information on coal tars published by the United States Geological Survey (USGS) and the work done with researchers at Oregon State University by Barbara Mahler, Ph.D., P.G., Research Hydrologist, Texas Water Science Center.

The work of the USGS was considered and included in the SAR. The SAR was revised to include the recent work from researchers at Oregon State University.

The SAR should discuss the uncertainty in applying potency equivalency factors (PEFs) as opposed to a whole mixture approach and describe the basis for choosing the PEFs from Nisbet and LaGoy (1992).

The SAR was revised after considering the additional information.

To address risk management information gaps identified in Section 3.3 of the Risk Management Scope for Coal Tars and their Distillates the following details from four integrated steel mills were provided: changes in point of impingement concentrations from coke oven batteries for benzene and benzo(a)pyrene due to implementing the province of Ontario’s SSS set; a breakdown of benzene releases reported to the NPRI in 2015; description of management & storage controls for coal tar; and four individual SSS action plans for benzene from each integrated steel mill.

The Government of Canada reviewed the information provided and determined that emissions from integrated steel mills present a continued concern for human health. No changes were made to the SAR. However this information will be taken into consideration during the development of risk management measures for coal tars and their distillates.

In response to information gaps identified in Section 3.3 of the Risk Management Scope document for coal tars and their distillates, it was indicated that after the province of Ontario implements a site-specific standard (SSS) for coal refiners, further information including the Emission Summary and Dispersion Modeling (ESDM) reports will be provided to Environment and Climate Change Canada (ECCC). 

The assessment of coal tars should be delayed until after the coal refiner’s application for a SSS under the province of Ontario’s air quality regulation is approved.

A coal tar refiner stated that its own refined air dispersion model has estimated concentrations of Benzo[a]pyrene four times lower than the results presented in the draft SAR.

Ontario published site specific standards (SSS) under Ontario Air Quality Regulation (O. Reg. 419/05) on November 21, 2017.  The standards were reviewed in order to inform the proposed risk management approach for coal tars and their distillates. This information was not considered in the risk assessment. The coal tar refiner did not provide any further information. 

Consider the effects of coal tar pavement sealers on Canadians who are asthmatics and the effects of PAHs on the cognitive and behavioural development of children.

Information and data on the effects of PAHs from coal tar products on asthmatics (Hew et al. 2015) and on the cognitive and behavioural development of children (Peterson et al. 2015) were considered. However, these studies were not included in the SAR because asthma triggers are not considered typical endpoints for determining critical health effects and there is a low risk to human health associated with exposures to the most prevalent PAH (naphthalene). Similarly, the Peterson et al. study (2015) was not included because effects on cognitive and behavioural development in children associated with prolonged prenatal exposure to PAHs are not compatible with application of a coal tar sealcoat as described in the dSAR, for which inhalation exposure risks are considered transient and low.

The runoff data reported in the study by Watts et al. (2010a, b) are not representative of runoff from a successfully sealed parking lot. The refined coal tar sealant (RTS) never cured, remaining as an aqueous emulsion which washed off the parking lot during the storm that occurred shortly after the emulsion was applied. The results of this study are therefore wholly unrepresentative of PAH or other emission factors that may be associated with sealed parking lots. As such, information derived from the study cannot be used to develop exposure scenarios.

The SAR was revised to incorporate data from four studies to determine the PECs of PAHs entering the Canadian aquatic environment in runoff from surfaces sealed with coal tar-based pavement sealants. Use of data from four different studies is intended to broadly represent the range of potential PAH concentrations that could be present in runoff from surfaces sealed with coal tar-based pavement sealants due to different application procedures and conditions.

Coke producing facilities operating in Ontario do not import coal tar-based pavement sealants.

Noted.

The approach set up under the Chemicals Management Plan (CMP) on the Petroleum Sector Stream Approach (PSSA) has not adhered to a predictable workplan by which stakeholders have the capacity to monitor and respond effectively to specific chemicals assessed under each designated Stream. The work that began in 2007 on the full list of priority substances captured under the PSSA continues to be in various stages of the assessment or management process, which makes it difficult for the public to monitor.

Petroleum substances are UVCBs: chemical substances of unknown or variable composition, complex reaction products, and biological materials. The assessment of petroleum substances is scientifically complex therefore methods and approaches were developed to better characterize their hazards and exposure.  

The planned publication timelines for the remaining petroleum substances are available in the List of substances in the third phase of CMP (2016-2020): December 2017 update.

Modelled point of impingement(POI) concentrations are not equivalent to “exposure” and should therefore not be used to determine human health effects.

Modelled concentrations of both PAHs and benzene “at the fenceline” use industry sourced data from the Canadian National Pollutant Release Inventory (NPRI). This approach is considered to be conservative and appropriate for assessing potential human health effects on local residents associated with nearby industrial facilities.

The statement that a margin of exposure (MOE) of 15,500 is “inadequate to protect … susceptible subpopulations” suggests that Environment and Climate Change Canada (ECCC) and Health Canada (HC) have adopted extraordinarily conservative MOE guidelines, above and beyond MOEs used in other instances. 

Consider adapting approaches developed by other agencies that have defined target MOEs for carcinogenic chemicals.

The SAR indicates that this MOE is “potentially inadequate to address uncertainties in the exposure and health effects databases”. The adequacy of MOEs depends on many factors, including the severity and nature of the toxic effect. The interpretation of MOEs in this SAR is consistent with the risk characterization in other risk assessments conducted under the Canadian Environmental Protection Act, 1999 (CEPA 1999). Other assessments applied MOEs of similar magnitude. For example, see Screening Assessment Petroleum Sector Stream Approach for Natural Gas Condensates and Screening Assessment Petroleum Sector Stream Approach for Liquefied Petroleum Gases, Stream 4 Petroleum and Refinery Gases.

The global approach applied in the SAR does not give an accurate representation of the current situation as it relates to coal tar emissions among Ontario coke makers.

The approach used in the SAR to evaluate exposure to emissions from coke-producing facilities in Ontario is appropriate to determine potential ecological and human health risks under section 64 of CEPA 1999. Information specific to Canadian facilities was used in the SAR when available, including site-specific information for the coke-producing facilities in Ontario provided by the Canadian Steel Producers Association.

The Government of Canada should consider conducting a risk-of-bias assessment and systematic review of the studies used in its evaluation of potential ecological impacts associated with the use of RTS.

All studies used to evaluate the potential for ecological harm in Canada were reviewed carefully to ensure data quality and reliability criteria were met.

We support the use of the science-based whole mixture approach to assess the potential human health effects of materials containing PAHs. 

We therefore support the resulting human health evaluations.

Noted.

Based on estimates of coal tar sealant use in the United States (US), the amount of coal tar sealant used in Canada may be as much as 10 to 20 times greater than the 10,500 tonnes listed in the SAR.

The statement in the draft SAR that coal tar pavement sealants are sold primarily at the retail level and by small companies should be verified. 

When the draft SAR was published, the proportion of coal tar-based pavement sealants used in Canada for professional applications was not available. This was acknowledged as an uncertainty in the SAR and the Risk Management Scope documents. Although this information gap for coal tar-based pavement sealant was identified in these published CMP documents, no additional data were provided during the 60-day public consultation period. 

Based on findings in the screening assessment and considerations in the Risk Management Scope document, the Government of Canada recently examined the import, manufacture, and sale of coal tar-based pavement sealant in the Canadian market. A mandatory survey was issued for coal tars and their distillates under Section 71 of CEPA 1999. Results of this data gathering initiative will better inform development of risk management activities.

Coal tar refining is a key component of a value chain, beginning with coal tars produced as a by-product by integrated steel mills. If not refined, this by-product would need to be disposed of as a hazardous waste, at high costs. Refining of coal tars produces key raw materials for downstream industries and functional users, including Canada’s aluminum industry (users of coal tar pitch), wood preservation (users of creosote), pigments (users of carbon black oil), and concrete and chemical manufacturing (users of naphthalene oil).

Noted.

Pollutant release and transfer data from the Commission for Environmental Cooperation Taking Stock online database demonstrate that between 2006 and 2013, the releases of PAHs (unspeciated) increased by almost two-fold. 

Noted.

There is no mention of the North American experience of using coal tar pavement sealers and the use of asphalt-based products as a substitute.

Given the evidence to demonstrate the impact of coal tar and their distillates to the environment, substantial effort by the Government of Canada in the area of identifying alternatives that do not exhibit the same toxicity traits as coal tars and their distillates is needed.

The Government of Canada is exploring ways to advance responsible replacement of chemicals of concern, including ways to apply informed substitution to support chemicals management (Combined government discussion paper and science committee report on informed substitution. Publication date: 2018-08-28).

Canada has not proposed to prohibit the use of coal tar sealants, while many US jurisdictions have. Effort is needed to identify alternatives to coal tars and their distillates that do not exhibit the same toxicity.

Sealant options that do not contain coal tar are already available on the market. 

The ecotoxicity evaluation should focus on the absence of real-world impacts, and the estimates of PAHs released to water related to runoff from coal tar-based pavement sealant parking lots are based on a failed coal tar-based pavement sealant application.

We therefore request a re-evaluation of the ecological assessment because these studies are not fit for purpose and are based on an out-dated sediment quality guideline approach.

Various lines of evidence were used to evaluate the potential for risk following exposure to coal tar-based pavement sealants and runoff from surfaces sealed with these products. 

The SAR was revised to incorporate data from four studies to determine Predicted Environmental Concentrations (PECs) of PAHs entering the Canadian aquatic environment in runoff from surfaces sealed with coal tar-based pavement sealants. The studies differed in approach and experimental design, and results from each were used to reduce uncertainties inherent within each study. Estimated concentrations of PAHs in the runoff were obtained by applying averages.

The sediment guidelines are derived mainly from studies reporting effects in field-collected sediments and therefore represent real-world exposure and effects. Values in these guidelines are also protective for long-term chronic exposures and for species that do not metabolize PAHs rapidly.

The most likely exposure is presumed to be application of coal tar sealers by a consumer on a 2 to 3 year cycle. However, this neglects the fact that this product is frequently used where children play: at schools, daycare centres, and residential driveways. Not only are these children more at risk because of their development, these exposures could be multiple times a week during certain seasons; much more than a homeowner applying a retail purchased coal tar pavement sealant.

The Government of Canada considers available data including various conservative exposure scenarios for the general population and for vulnerable populations. Given the limited information available on the application of pavement sealants at schools, this potential exposure is acknowledged as an uncertainty in the SAR.

The draft SAR notes that the MOE applied to determine the risk to human health and the environment were inadequate. This should provide sufficient grounds to demonstrate a need for greater protection of the environment and human health.

Noted.

A stakeholder questions the use of PAH concentrations in dust and soil in calculating the ingestion rate. The SAR should consider dust ingestion only and not the combined soil and dust ingestion rate. Additionally, the SAR should not assume that soil and dust concentrations of PAHs from coal tar-based pavement sealants are equal.

Where elevated PAH levels in household dust are attributed to coal tar-based pavement sealants, it was assumed that PAH would also be present in the soil and dust nearby. There is lack of information on specific locations where children might play and there are no use restrictions for these sealants. Therefore, the Government of Canada is applying a precautionary approach by assuming that individuals may be exposed to PAH in both soil and dust from coal tar-based pavement sealants, and that soil PAH concentrations are similar to those measured in indoor dust.

A stakeholder questions the use of forestomach benchmark dose values (BMDL). If one considers all BMDL10 derived by ECCC and the US Environmental Protection Agency (EPA) that do not include forestomach tumours (i.e., skin, liver, esophagus, tongue, and larynx), the lowest BMDL10 value is 3.15 mg/kg-day (esophagus) (ECCC, 2014), which is about 6-fold higher than the forestomach BMDL10 values.

Although there is some disagreement about the use of forestomach tumour data for deriving points of departure, HC and the US EPA both consider it as being suitable for this purpose.

It is recommended that ECCC reconsiders its use of “predicted environmental concentration” (PEC) for evaluation of PAH concentrations and of “predicted no-effects concentration” (PNEC) values for individual PAHs. Sediment PAH concentrations are rarely predictive of toxicity and PAHs are virtually insoluble in water, resulting in a general absence of aqueous impacts. For PAHs, equilibrium partitioning approaches and the concentration of PAHs in sediment pore water more accurately predict sediment toxicity.

Several lines of evidence were considered to determine potential ecological risks. One of these lines of evidence involved the quantitative comparison of PECs for PAHs released in runoff (from surfaces sealed with coal tar-based pavement sealants) with PNECs in the Canadian aquatic environment. PECs in the SAR were revised to incorporate data from four different studies, to better consider the range of potential PAH concentrations that could be released to the environment under various application procedures and conditions. 

The Canadian Council of Ministers of the Environment (CCME) water quality guidelines are real-world effects values that are designed to be protective for long-term chronic exposures and for species that do not metabolize PAHs rapidly. Therefore, the resulting risk quotients add a line of evidence supporting the conclusion that there is potential risk to aquatic organisms from the release of PAHs present in coal tar-based pavement sealants runoff to the Canadian environment.

Because bioavailability of PAHs is likely lower from dust than from the diet, application of the benzo(a)pyrene toxicity value without accounting for differences in bioavailability from diet vs. dust (i.e., assuming 100% bioavailability from ingestion of PAHs in dust, as was assumed by ECCC) likely overestimates PAH exposure and risk from coal tar-based pavement sealants in house dust.

Given the lack of reliable data for the bioavailability of PAH measured in dust samples, it was considered appropriate to not apply a bioavailability factor. The uncertainties section in the SAR was updated to clarify this.

The proposed risk management initiative is not supported by the scientific findings reported in the dSAR.

In Section 10.3 of the dSAR, three potential exposure scenarios to coal tar-based pavement sealant are evaluated:

1. Risk from PAHs in house dust associated with the use of coal tar-based pavement sealants,
2. Risk from inhalation exposure to coal tar-based pavement sealant application, and
3. Risk from dermal exposure resulting from coal tar-based pavement sealants.

None of the three potential exposure scenarios were considered as below a low level of concern for public health.

The first scenario is a proposed risk to human health and was determined as toxic under Section 64 of CEPA 1999. The MOEs for the first scenario were determined to be potentially inadequate. Therefore, further risk management is proposed. No risk was identified for either the second or the third scenario.

The margin of exposure is based on the compositional analysis of a suite of 16 PAHs. Recent data analyzing a larger suite of 60 PAHs reveals a greater concentration and proportion of potentially harmful PAHs to which the general population may be exposed which would further reduce the margin of exposure.

Coal tar-based products should not be sold because raising PAH levels for these types of sealants is polluting our already fragile waters and causing unnecessary health risks.

The final SAR proposes that coal tars and their distillates are toxic under Section 64 of CEPA 1999. The Government of Canada proposes that further action be taken on these substances to reduce their risk to human health and the environmental, notably the development of regulations that would prohibit the manufacture, import, and sale of coal tar-based sealant products in Canada. Please see RM APPROACH LINK for further details on the proposed path forward for risk management of these substances.

Stakeholders are pleased that the Government of Canada is reviewing coal tar and related substances that are currently being used in Canada, and addressing the concerns associated with these substances.

Stakeholders support the findings that six substances defined collectively as Coal Tars and Their Distillates are toxic under Section 64 of CEPA 1999.

Noted.

The province of Ontario’s SSS process achieves the same objectives that the Chemical Management Program would achieve by regulating coal tars and their distillates by applying established risk management actions to reduce emissions from coal tar storage and loading. It is not necessary for the federal government to establish additional initiatives to address emissions from coal tar storage and loading.

The Government of Canada considers existing regulatory requirements at the federal, provincial, and municipal levels to determine their proposed risk management approaches. The Government of Canada will monitor actions taken and resulting emissions, and re-evaluate the need for additional federal action in 2022 after implementation of Ontario’s SSS for steel mills.

It is unclear why risk management actions taken in other jurisdictions are relevant for the risk management scope for coal tars and their distillates.

In cases where appropriate data from Canada are not available, relevant, high-quality data from other jurisdictions with similar lifestyles, geography or climate (such as the United States and European countries) are considered. 

The Government of Canada’s proposed management of coal tars and their distillates will not be fully protective of the environment or human health if it relies on current CEPA management regimes for PAHs and benzene, including the Environmental Code of Practice for Integrated Steel Mills (PAHs and benzene) and a Code of Practice to Reduce Fugitive Emissions of Total Particulate Matter and Volatile Organic Compounds from the Iron, Steel and Ilmenite Sector.  This management regime is inadequate because it relies on non-regulatory measures to create the necessary protection from coal tar for the environment and human health.  An effectiveness review of existing federal and provincial risk management actions for PAHs and benzene is needed and should be expedited.

In June 2017, ECCC published a Pollution Prevention Planning Notice to reduce NOx, SOx, and VOCs emissions from the iron, steel, and ilmenite sectors. Facilities will have to report annually on progress in implementing the code of practice to reduce fugitive VOCs and total particulate matter (TPM). This will help to reduce emissions of benzene and PAHs. 

Also, the province of Ontario is now applying SSS for benzo(a)pyrene (a PAH) and benzene at all steel mills, which will require monitoring and control of VOCs (benzene) and particulate (PAH) emissions. ECCC will monitor results of these actions and re-evaluate the need for additional federal action.  

The proposed risk management objectives for coal tars and their distillates are too narrow in scope. The objectives should focus on preventing and eliminating coal tars, rather than minimizing, as efforts to minimize will likely result in ongoing exposure.

It is not feasible to prevent and eliminate coal tars and their distillates for all sectors or activities in Canada. Appropriate management of these substances throughout their life cycle will prevent or minimize their release into the environment.

The Government of Canada is proposing further actions for these substances to reduce risks to human health and the environment through regulations that prohibit the manufacture, import, and sale of coal tar-based sealant products in Canada. The Government of Canada also proposes to reduce air emissions from industrial activities to protective levels, while considering technical and economic feasibility and socio-economic factors for these substances.

Additional consideration should be given to evaluate how the risk assessment conclusions for Coal Tars and Their Distillates could be used to review the adequacy of managing polycyclic aromatic hydrocarbons (PAHs) and benzene under CEPA 1999.

Noted.

Stakeholders support the inclusion of technical and economic feasibility within the proposed risk management objective for coal tar refining, together with consideration of socio-economic factors.

Noted.