Property developer Telford Homes is restarting exploratory works at a contaminated construction site in Hackney Wick.
Trial assessments began on 28 November to assess the current level of volatile vapours and odours on site, alongside a community drop-in session run by the developer to keep residents informed of ongoing work.
Excavation at the Stone Studios redevelopment site on Wallis Road was halted following complaints from residents and the nearby Mossbourne Academy school in September of unpleasant symptoms caused by noxious fumes released from the site, including headaches and nausea.
Some residents were left unimpressed with Telford Homes’ communication style, with resident Peter Bennett saying: “A load of boards with 2-dimensional figures and arrows is how you teach kids about the environment.
“We want data, and proper monitoring, and assurances that the methodology when it comes to drilling and extracting will not cause the same kind of thing or worse.
“Why won’t they commit now to installing air quality monitors? You can pick one up online for a few hundred quid.”
Telford Homes has stated that, whilst passive air quality monitoring is ongoing for average concentrations of volatile organic compounds in the air and reported back to Hackney Council and London Legacy Development Corporation (LLDC) weekly.
The developer adds: “Providing general air quality monitoring of the local area is not a requirement for the construction process.
“We understand that general air quality and pollution is a particular concern. In response to members of the community, the project team is going to look into air monitoring devices further. We will then review the possibility of installing additional air quality monitors in the area.”
A report released by site investigators RSA Geotechnics back in May had predicted that a “significant” proportion of the volatile contamination would be released into the atmosphere when excavations reached groundwater level, with drilling crews all reporting an increase in the smell when shallow levels were initially reached.
Telford Homes has admitted to residents that the precautions taken in excavations were not sufficient to prevent the release of vapours.
In material displayed on boards in a community drop-in session on the 27 November, the company states: “We were aware about the contaminated soil, and had a process in place to limit the risk of odours being released.
“Unfortunately, those measures did not prove to be resilient enough to control the release of bad smells.”
Hackney Council confirmed the cause of the vapours as the historic contamination of the site’s land by hydrocarbons, including benzene and naphthalene, with chemicals found in concentrations in the ground to a depth of 3-4m posing a ‘high risk’, according to a May environmental report.
Telford Homes added: “The level of these chemicals in air has been measured by our specialist consultants RSA. The concentrations found by monitoring were well below a level considered to be harmful by regulatory bodies.
“Although the odours released were recorded to be within safe limits, some people may react to them even at very low levels.”
The exploratory works are being carried out following Hackney Council warning Telford Homes in October that the developer’s rethought strategy did not go far enough in mitigating the effect of the vapours caused by the excavation of contaminated land, or in satisfying the community’s concerns.
One of the individuals who has complained of noticing ill-effects was Hackney Council’s principal pollution control officer for land, air and water Robert Tyler, in a letter to Russell Butchers, senior planning development manager for the London Legacy Development Corporation (LLDC).
Referring to an 18 October public meeting held between residents and Telford Homes, Tyler said: “One lady raised the issue of her sinuses and eyes being affected by the emissions yesterday. I have to admit that prior to her comments I had also found my eyes to be slightly affected, although I can’t be sure that it was the emissions from the site.
“I’ve reviewed the RSA Remedial Strategy dated October 2018 and attached method statement… and currently do not think that sufficient actions are set out.
“It is obviously essential that the updated action plan is water tight. I would suggest a technical presentation with representatives of the community to provide final scrutiny on any document.”
The exploratory works will have a trigger to cease works of air quality readings of 0.5 parts per million (ppm) of chemicals in the air recorded at the boundary of the site.
This stands in contrast to the initial strategy of works ceasing if levels of over 10ppm were recorded.
The site has been in industrial use since the Victorian era, with the first plastics in Britain produced there from 1866. Vulcanised rubber, iron, rope, dye, and varnish were all produced within the area by 1870, with several works using noxious substances on Wallis Road.
A spokesperson for Telford Homes said: “Ahead of any excavation works re-starting, Telford Homes will be undertaking a number of short-term assessments on site to ensure that the process can continue safely and that disturbance to neighbours is minimised.
“These assessments will help us to identify the most effective way to reduce the concentration of contaminants in the soil, which caused the unpleasant odour to be released.
“These assessments will start from 28 November and last around a week.
“Excavation works will not restart on site until these assessments have concluded, and a new remedial strategy and revised methodology have been agreed with LLDC and Hackney Council. Telford Homes will continue to liaise with local residents, schools and businesses to keep them up to date on developments.”
A spokesperson for LLDC said: “Telford Homes has worked with LLDC, the London Borough of Hackney and Public Health England on plans to minimise the impact of the works at Stone Studios on the community and the surrounding area of excavation works.
“The authorities have approved a limited trial of the proposed methods which will help determine when and how full excavation work can resume. Telford Homes will continue to liaise with local residents, schools and businesses to keep them up to date on developments.”
“We have previously requested that all activity on the site is stopped, and are keen that full work only restarts if LLDC and Telford Homes can reassure the local community and the council that any contamination is properly managed, the impact on local neighbours is minimised, and the site’s neighbours will be kept properly informed.
“We will continue to keep a close eye on developments including the results of the trial excavations taking place this week.”