PLANTS are believed to have poisoned dogs which fell ill after visiting public land used for Olympic development - allaying fears the site had been contaminated by building work.

Initial findings of an investigation by the Environment Agency suggest the three animals were suffering the effects of consuming Giant Hogweed on Leyton Marshes, off Lea Bridge Road.

The probe was launched when campaigners opposed to the use of the site for a temporary basketball training centre raised fears that toxins unearthed during construction work were to blame.

One of the dogs was diagnosed with chemical poisoning while the others had burns around their mouths.

They are expected to make a full recovery.

However, the Save Leyton Marshes group still insist piles of rubble it claims contain asbestos still pose a risk to health and the environment.

Member Claire Weiss said: "We don't think it's a safe place to be at all. I'm pleased the dogs were not harmed by the rubble but it still presents a risk.

"The covers are often blown off and it means this dust blows into people's faces and the atmosphere itself."

A spokeswoman for the Environment Agency said: "During the investigation we did find two large clumps of Giant Hogweed, a UK invasive species, and when touched these release a sap that is poisonous and will give symptom that look very similar to chemical burns.

"Preliminary results indicate the water courses including the ditches are healthy and contain wildlife that would normally be expected in marsh areas."

Campaigners claim the temporary structure will cause lasting damage to the protected land, which the Olympic Delivery Authority (ODA) denies.

Protesters were evicted after blocking construction work on the site last month and they claim the ODA has dug deeper than it has permission to.

An ODA spokesman said: "We have not been made aware of any link between construction activity on Leyton Marsh to dogs becoming ill.

"The soil at Leyton Marsh does not represent any significant risk to site workers and certainly not to local residents, nor has there been any breach of any codes of practice.

"We are currently finalising plans with Waltham Forest Council to remove the remaining soil and will remain in close contact with statutory bodies as appropriate.”

The Environment Agency has confirmed that the excavated material does not represent a significant risk to the River Lea or to groundwater.

"We will continue to work with statutory bodies as required and our own health and safety experts are routinely monitoring the site."

The full findings of the agency's investigation are not expected to be published until the end of next week.

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