TESTS have shown not all material dredged for a vast new quay at Teesworks will be suitable for disposal at sea.

Worry and frustration over dead crustaceans washing up on Teesside’s coastline has sparked protests and calls for action since late last year – with concern livelihoods are being devastated. A fresh investigation by Defra and partner agencies published last month found a harmful algal bloom in the area was identified as of “significance” – but dredging continued to be ruled out as a likely cause of the trouble.

No single consistent causative factor was identified. Work is continuing on the £107m South Bank Quay to offer a link to the River Tees for manufacturers at Teesworks.

Bosses hope the first 450m of the 1km quay will be complete between Easter and June 2023. Teesworks bosses say no dredging has taken place for the project yet, but activity is due to take place later this year – with the channel deepened and dredged to a depth between 11m and 15m.

Correspondence seen by the Local Democracy Reporting Service shows the first phase of works by John Graham Construction’s subcontractors will include dredging within the turning circle of the Tees opposite Tees Dock, and the berth pocket of the new quay once it is constructed. In the email, Tees Valley Mayor Ben Houchen confirmed sampling had been carried out in accordance with regulation and the terms set out by the Marine Management Organisation (MMO) permission.

The message added further tests were carried out under the instruction of the MMO after initial groundwater investigations – with mapped out areas where dredged material “will not be suitable for disposal at sea”. The mayor’s correspondence added: “Protection of the Tees environment is a priority and is acknowledged as being very important to the delivery of this project, and all dredging and disposal operations will be undertaken in full compliance with the requirements of the MMO and related regulations and guidance.

“Different options regarding the disposal of the dredged material that cannot be disposed of at sea are presently being looked into, advice is being sought and taken and the final proposal for the land disposal is to be decided.” The 18-page MMO licence for the first phase of the South Bank quay offers more detail on the dredging planned.

Material dredged near the south bank of the Tees near the quay between four co-ordinates has been excluded from disposal at sea, with an “enclosed bucket” to be used. The reason given was: “To prevent contaminated material being disposed of at sea or mobilised causing toxic or harmful effects to sensitive receptors.”

In March, Mr Houchen told a Tees Valley Combined Authority (TVCA) cabinet meeting that dredging had taken place in the mouth of the Tees further out to sea on behalf of the statutory harbour authority – PD Ports. At the time, a PD Ports spokesperson said they continued to fully support the MMO, the Environment Agency, Defra and other official bodies to provide information for their ongoing enquiries which had “ruled out dredging” as a possible cause for crustacean deaths.

There were fresh concerns in May when piles of dead sea creatures including crabs, lobsters and razor clam shells were noticed littering the beaches at South Gare near Redcar and along the coast to Hartlepool and Saltburn. Defra’s joint investigation last month repeated dredging had been ruled out as a likely cause of the problems – with the probe stating the disposal of dredged sediment would not be stopped.

The report stated: “The MMO uses the best available evidence to inform its decision making. There is no evidence to suggest that the disposal of dredged sediment is responsible for the crab and lobster mortality – this has been tested in accordance with international obligations.”

Last week, Stockton North MP Alex Cunningham called for a “full investigation” into dredging in the Tees after sharing fresh doubt about the “algal bloom” theory. He said: “Testing dead crabs and visits from ministers are all fine and well but we need to see real action from the Government to get to the bottom of this.”