Patches of grass were left apparently scalded by the chemical [George Carden/BBC] A field had to be cordoned off on Sunday night following the discovery of a chemical substance. Sussex Police said the field, near Lynchet Close in Brighton, was closed after the substance was discovered by a member of the public earlier in the day. The force said the material had been assessed by specialists and was deemed to pose no wider public health risk, unless direct contact was made with it.