A Fenland road was closed and diversions put in place while emergency services dealt with a chemical spill from a farm sprayer.
Around 2,500 litres of diluted herbicide leaked from a sprayer for about a quarter of a mile as it was being transported.
Residents in Lakes End, near Welney, were told to stay inside while the fire service used specialist mats to absorb the spilled materials.
At the scene, Tim Edwards, station manager at King’s Lynn fire station manager, said: “Our priority is to make sure residents are protected.
“We must also be aware of the chemical could carry a danger to any aquatic life.”
He added: “We will now be working closely with the environment agency and highways on the clean up.”
Crews from King’s Lynn, Wisbech and Littleport were called to the incident at around 9.20am yesterday together with a vehicle carrying specialist equipment to clear chemical spills.
Police enforced road closures for about six hours at Silt Road, Horsehead Drove and the junction of Wisbech Road and New Road.
The chemical was a diluted agricultural herbicide which is sprayed on wheat at this time of year to control weeds.
It mainly spilled along the A1101 and Cock Fen Road.
Barry Lewis, who lives in Cock Fen Road, said: “I needed to post a letter this morning, so I cycled to the top of the street.
“Then a tractor went by and it was spilling out bright yellow chemical. Afterwards, I went to my daughter’s and was told to stay there all morning while the emergency services got to work.”
He added: “I’m allowed back now but I am a bit worried about my cats because I haven’t seen them since.”
An investigation is under way to assess the damage.
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