A chemical leak from a former industrial site [formerly owned by Bayer Cropscience] which was supposed to have been cleaned up for housing has resulted in a formal warning for developers...Landowner Harrow Estates is currently monitoring results of its work to rid the site of pollution...Harrow Estates will have to convince South Cambridgeshire District Council that remediation has been successful...Jenny Daly, the company's managing director said..."Our contractors Vertase took very prompt action in blocking the pipe".