Environmental campaigners are taking legal action over a fleet of rusting US navy vessels heading to the UK for wrecking.
Friends of the Earth will ask the High Court in London to quash a modification to a waste management licence allowing the work to go ahead.
Three Hartlepool residents are also applying to the court on Wednesday, for an
immediate injunction to stop the ships arriving.
Neil Gregan, Stephen Hall, and Ben Marley, who all live near the Able UK site where the ships are due to be dismantled, say they could pose environmental risks to ecologically-important sites nearby.
On Tuesday there was confusion about whether the so-called "ghost fleet" - contaminated with chemicals including asbestos and heavy diesel - would be allowed into the UK.
Transport Secretary Alistair Darling did not act on calls to send the ships back, with a Transport Department spokesman saying responsibility lay with the Environment Agency.
He said the department only had jurisdiction to assess if the ships were seaworthy.
The Environment Agency has already described the licence allowing the wrecking work to go ahead as "invalid".
But it said it had no powers to turn the ships away.
The four vessels are being towed on a 4,000-mile journey across the Atlantic.
They are now near the Azores, and are due to dock in Hartlepool in mid-November.
The ships are not carrying any cargo, but the problem is in their own ageing fabric.
Some of the ships were built in the 1940s when asbestos was widely used to line boilers, for example, and toxic chemicals were used in their wires.
The Environment Agency said the licence to carry out the work had become invalid because it had been granted on the understanding that all the relevant planning permissions were in place.
But Hartlepool Council later said the necessary planning permissions had not all been granted.
Able UK insisted it had all the consent it needed, and also stressed it could handle all the dismantling and recycling safety.
The Environment Agency said it was continuing to negotiate with Able UK and the US authorities.
The Liberal Democrats warned that the ships may arrive before the issue has been resolved - leading to potentially catastrophic environmental problems.
"Because of this farce, will the ships now have to drop anchor in British
waters and wait for the relevant permissions?" said
Norman Baker, Liberal Democrat environment spokesman.
"It is grossly unacceptable to have old, decrepit vessels contaminated with
PCBs [polychlorinated biphenyls], asbestos and fuel oil, waiting in stormy British waters for that
"If they break up, the environmental impact will be devastating."
On Monday, the government promised to re-examine the circumstances surrounding the original deal between US authorities and Able UK.
The ships were subject to legal wrangling before they even left the US.
The original deal was for 13 ships, but nine are remaining in the US for the time being, following a last-minute injunction in a US court.