Request ID: FOI-0929-2324 Date published: 20 July 2023
You asked
Hi, could you please confirm whether or not asbestos air monitoring are or have been implemented near overground shafts to ensure safety of the public?
If not, could you please explain what precautions are in place to ensure ventilation shafts do not cause asbestos exposure to the public when exhausting dirty air?
Could you please explain how ballasts contamination are monitored on the underground and overground.
Could you please confirm wether or not ballasts on the underground and overground could be contaminated with asbestos and what is done to avoid such contamination.
Could you please list the locations/lines of the under and overground where ballasts have been completely replaced or cleaned from asbestos contaminations.
Thank you
We answered
TfL Ref: EIR-0929-2324
Thank you for your request received by Transport for London (TfL) on 26th June 2023 asking for information about asbestos and ventilation shafts / ballasts.
Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our information access policy.
Specifically you asked:
“Hi, could you please confirm whether or not asbestos air monitoring are or have been implemented near overground shafts to ensure safety of the public?
If not, could you please explain what precautions are in place to ensure ventilation shafts do not cause asbestos exposure to the public when exhausting dirty air?
Could you please explain how ballasts contamination are monitored on the underground and overground.
Could you please confirm whether or not ballasts on the underground and overground could be contaminated with asbestos and what is done to avoid such contamination.
Could you please list the locations/lines of the under and overground where ballasts have been completely replaced or cleaned from asbestos contaminations.”
I can confirm that we hold the information you require.
Asbestos fibre release via vent shafts is controlled by adopting control measures during any work on or near asbestos. This would include tunnel locations wherever that work is required to be done, and could include areas close to ventilation shafts. Any such work is carried out in accordance with the Control of Asbestos Regulations 2012, and consequently the control measures employed ensure that fibre release into the tunnel environment is minimised. Although not a requirement of these regulations, reassurance air monitoring is frequently undertaken during this type of work and airborne fibre levels are well below the control limit. Hence by adopting these measures, air quality in tunnels is maintained within the Health and Safety Executive limits and therefore any air that is released to atmosphere via the vent shafts is also within these limits.
Prior to any track stabilisation or reconditioning work, ballast contamination is monitored by undertaking sampling and analysis for a whole suite of contaminants in order to assess the risk during handling, and if being removed from site to determine how it is to be disposed of. Historically asbestos has been used for various applications in tunnels, one of the most common being ‘troughing’, which was used as containment for cables running within the ballast. Over the years, much of this material has been removed but a significant amount still remains. In accordance with the Control of Asbestos Regulations 2012, the condition of asbestos containing materials are monitored by undertaking regular re-inspections and remedial action is taken if the condition of the material deteriorates, thus maintaining it in a safe condition.
In response to your request to provide a list of the locations/lines where ballast has been completely replaced, note that the London Underground is 160 years old, and your request as worded covers the entirety of this period. Ballast replacement has been undertaken at many locations and we are unable to compile such a list within a reasonable timeframe. This aspect of your request is therefore being refused under Regulation 12(4)(b) of the EIR on the basis that it is “manifestly unreasonable”. The purpose of the exception is, to cite the guidance from the Information Commissioner (see here) “...to protect public authorities from exposure to a disproportionate burden or an unjustified level of distress, disruption or irritation, in handling information requests.” The use of this exception is subject to the ‘public interest test’, which requires us to consider whether the public interest in applying the exception outweighs the public interest in disclosure. We recognise the need for openness and transparency in the operation of our business, and the fact you have requested the information demonstrates that there is an interest in it. However, given the broad scope of the question and the excessive amount of time it would take to provide it - which would divert a disproportionate amount of our resource - on balance we consider that the public interest currently favours the use of the exception.
Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.
Yours sincerely,
David Wells FOI Case Officer FOI Case Management Team General Counsel Transport for London
