Monitoring data on certain heavy metals, loss on ignition (the change in weight recorded when the ash is heated to a high temperature) and the total organic carbon in incinerator bottom ash is provided by the incinerator operators. This is placed upon the Environment Agency public registers. These data are checked by the Environment Agency upon receipt. Limits are set on loss on ignition/total organic carbon to ensure that the incinerator is operating efficiently. No breaches of these limits have been reported hence no enforcement action has been taken. Limits are not set on the heavy metal content of the ash as a permit condition. The operator is expected to carry out more detailed analysis before the ash can be disposed of.