Most of AEP's chemical releases reported on the TRI — typically about 80 percent — are emitted to the air from power plant stacks.

The bulk of our air releases take the form of hydrochloric acid aerosol (HCL). Trace amounts of chlorine are naturally present in coal. When the coal is burned, the chlorine is released in small amounts, some of which combines with hydrogen in the air to form hydrogen chloride. As the hydrogen chloride travels through the exhaust gas in the power plant’s stack, it reacts with moisture in the air to form hydrochloric acid aerosol, which becomes more diluted as it exits tall stacks and disperses into the atmosphere. Because AEP is such a large consumer of coal to generate electricity, it is not unusual to see this type of chemical release at the top of the TRI list.

About 20 percent of AEP’s TRI releases are in the form of coal combustion products Coal Combustion Products (CCPs). The majority of the CCPs are transferred to landfills regulated by environmental agencies and maintained by AEP. Some of the CCPs are recycled into other products. For example, CCPs can be used in concrete blocks, road-fill material, plastics and paint. Elements in CCPs include antimony, arsenic, barium, beryllium, chromium, cobalt, copper, lead, manganese, mercury, nickel, selenium, thallium, vanadium and zinc.

Releases to water, which are carefully monitored in compliance with water quality regulations, represent less than one percent of the releases we report. These include the chemicals in CCPs (listed above), chlorine, and ammonia.