On the 13th April 1999 the Environment Agency wrote with regard to the persistent hydrogen chloride breaches and asked why the plant's authorisation should not be amended to exclude PVC (which London Waste had identified as the cause of many HCl breaches). The reply was not on the public register when Greenpeace viewed it.
In December 2000 London Waste Ltd. commissioned REC Ltd. to monitor some of the pollutants emitted from its stack. They found that emissions of oxides of nitrogen from the chimney were above the authorised limit for 25 of the 26 hours monitored.