Task 2b – Update on Regulatory Discussions and Position

There is no current formal regulatory position in Scotland to permit the use of AWCCT under Clause 948 of the Specification for Highways Works. In England, the Environment Agency ‘Regulatory Position Statement 075’ (RPS075) applies and allows the use of treated asphalt waste containing coal tar for hard paving in England without an environmental permit, provided certain conditions are met:

  • The material must meet all the requirements of the appropriate ‘Specifications for Highway Works’.
  • The material is only used in sub-surface, not surface, layers.
  • The relevant objectives of the Waste Framework Directive are met, i.e. there is no risk to human health, no damage to the environment, no deleterious effect on the countryside, nor any nuisance caused by noise or odours

Regulatory dialogue with SEPA’s National Operations Waste Unit during Task 1 confirmed that SEPA is currently developing a Position Statement on the reuse of Asphalt Waste Containing Coal Tar (AWCCT) cognisant of SEPA’s waste to resources framework. This position statement is anticipated to broadly align with the Environment Agency’s (EA) Position Statement 075 which allows reuse as a Clause 948 material .

Towards the conclusion of the Task 1 works, ADEPT released an updated version of their “guide to managing reclaimed asphalt”. This provides additional advice on the identification and management of AWCCT and appears to align with the EA position. It is understood that SEPA is considering the applicability of the ADEPT guidance relative to the Scottish waste regulatory regime. At the time of writing in March 2022, the Regulatory Position Statement is yet to be published by SEPA and no date of publication has been announced. 

Transport Scotland’s Pavement Forum was also liaising directly with SEPA on the cold bound recycling options for asphalts as part of a wider approach to managing asphalt under a separate project. These discussions focussed around the development of a TS Guidance document detailing an approach to the cold recycling of bitumen and coal tar road surfacing utilising Clause 947 and 948 of the Specification for Highways Works. In February 2021, Transport Scotland published this guidance document which draws on the principles of SEPA’s draft position statement. 

Transport Scotland’s position largely advocates the use of AWCCT in a cold recycled base or binder layer irrespective of the degree of coal tar presence or whether it could be classified as Hazardous Waste if removed from site. It emphasises the need to provide appropriate information to SEPA to allow them to assess the proposed use and provide prior approval of the proposed works. It provides guidance and a framework by which operators can demonstrate to SEPA that they meet their requirements, thus streamlining the process. It is understood that this approach has been completed at a number of sites within the TS road network with agreement from local SEPA teams. 

The outcome of the TS and SEPA discussions around the TS guidance suggests that AWCCT can potentially be recycled across the network under Clauses 947 and 948 without an upper cap on coal tar concentrations, which theoretically addresses the clarification sought from SEPA to determine the requirements of a site-based tool i.e., is it required for solely identifying construction worker risks or will it feed into supporting the identification of materials management options including waste classification for disposal. The TS position therefore directs the key objective of a site screening tool to the determination of whether coal tar is absent (which would allow the application of hot recycling) or not (and therefore require cold recycling or disposal). A tool would however also remain useful for waste classification on site supported by laboratory analysis.

SEPA’s regulatory compliance position is to apply the Technical Guidance WM3 “Waste Classification: Guidance on the classification and assessment of waste” (1st edition 2015) to determine when AWCCT contains sufficient coal tar to be deemed “Hazardous Waste” and fall under List of Waste Code 17 03 01(bituminous mixtures containing coal tar) as opposed to the Non-Hazardous code 17 03 02 (bituminous mixtures other than those mentioned in 17 03 01). There does however remain ambiguity in the WM3 assessment protocol with two options provided for the assessment of AWCCT depending on whether the quantification of coal tar is known or not. Typically, current industry practice is to assume that it is not possible to determine the percentage of coal tar within a binder/ road core given the complexity of coal tar composition. Therefore, WM3 advocates the use of benzo(a)pyrene (BaP) as an indicator compound to estimate when polycyclic aromatic hydrocarbons (PAHs) are likely to be greater than 1000mg/kg (0.1%) and hence coal tar is likely to be present. It is also notable that whilst WM3 is explicit that a BaP concentration above 50mg/kg would indicate sufficient coal tar for a material to be deemed Hazardous, it is not explicit that a concentration lower than this threshold is automatically Non-Hazardous. 

This is an area of ambiguity in the WM3 guidance which is further blurred by the statement in an earlier paragraph that “assessments based on PAH’s alone are not consistent with the legislation and cannot be used to classify a waste as Non-Hazardous”. The current wording in WM3 therefore leaves industry and facilities which receive waste to interpret when coal tar content in a material is sufficiently low for it to be classified as Non-Hazardous (17 03 02) and whilst ADEPT has published non-statutory industry-led guidance setting out a recommended standardised approach, variable methods of analysis and assessment are often used by different analytical laboratories and organisations leading to inconsistent outcomes. Figure A1 in Attachment 1 presents a graphical summary of the above.

WM3 also introduces uncertainty by explicitly linking this guidance to what it calls “’Black top’ (road surface) waste” rather than the phrase “road asphalt waste containing coal tar (AWCCT)” which is also used in the same section of the guidance. It does not however define what it means by “black top” and how this might differ from AWCCT (if at all). An extract of WM3 is provided in Attachment 2 for information.

Following the above TS and SEPA discussions, it was agreed with the SRRB project steering group that further regulatory discussions are not currently warranted as part of this SRRB work unless there is a challenge on the approach adopted by the published TS position statement/ study. 

As described above, one of the issues that has been identified is the lack of clear guidance within WM3 for when AWCCT can conclusively be classified under Non-Hazardous List of Waste Code 17 03 02 (bituminous mixtures other than those mentioned in 17 03 01). It is however understood that WM3 is currently being updated but it is not known if there are plans to change the guidance for AWCCT. It is recommended that industry lobbies SEPA and the EA to provide greater clarity regarding the assessment criteria required to conclusively classify AWCCT with incidental coal tar content as Non-Hazardous (17 03 02).

It should be recognised that the underpinning definition of what makes waste Hazardous may mean that the effect of clarification may be the lowering of the threshold or increasing the complexity of the assessment. Therefore any industry lobbying to amend the current WM3 approach should also take account of the sustainability and commercial challenges associated with the current availability of Hazardous Waste facilities in Scotland when assessing its viability.

Giving the industry better guidance to allow waste producers and waste receivers to confidently and correctly assign AWCCT with incidental coal tar content as Non-Hazardous (17 03 02) will not only have a big commercial impact on the cost of waste disposal but also reduce the precautionary mischaracterisation of all AWCCT as the Hazardous waste stream 17 03 01. 

Whilst there have been indications that a Waste Management Facility in Scotland may start to accept AWCCT (17 03 01) again, there are currently no licenced landfills within Scotland that accept this Hazardous waste stream. As such it is understood that excess AWCCT is being dispatched to Northern England or the Netherlands. Even if a Scottish Waste Management Facility begins accepting AWCCT (17 03 01) again, capacity will be limited and any misclassification of AWWCT with incidental coal tar content as Hazardous will result in the potentially unnecessary consumption of this limited landfill capacity.