ENMAX has a formal process in place for monitoring, reporting, and responding to environmental incidents that have the potential to impact human health, land, vegetation, or water. The types of incidents that occur in operations are typically releases of mineral oil from transformers and hydraulic oil from vehicles. Although these substances are relatively inert, a major release could have an environmental impact. 
We take prudent steps to avoid such releases, including implementing a comprehensive leak detection and management program and a formal spill response and mitigation program. When leaks or staining are found on equipment during inspections, they are marked on the inspection form, entered into a computer database and managed accordingly. Minor leaks are repaired onsite, while major equipment repairs and others requiring power outages to allow repair are continually monitored and repaired in order of priority by field crews. All transformers returned to the shop are also inspected for damage.
We respond immediately to all significant spills and report these to Alberta Environment and appropriate regulatory bodies. Spills are deemed significant if they contain PCB concentrations greater than 50 ppm, have created or have the potential to create an adverse effect on the environment, such as entering a water body, or are in excess of 100 litres. In 2007, nine significant releases of transformer oil occurred with a total volume of 3,067 litres. PCB concentrations were less than 1 ppm in all instances.
All environmental releases are managed according to our spill management program. Any spills causing or having potential to cause adverse impacts to the environment are cleaned-up immediately. Out of the nine sites in 2007 where significant releases occurred, seven have been cleaned up and two are currently being risk-managed. Risk management is a term used to describe sites where a complete clean-up is not feasible due to location and timing, or is not necessary due to zero risk presented to the environment. Risk managed sites are recorded and monitored periodically and are cleaned up (remediated) at a future date.