Toxic chemicals released in Hawaii from facilities such as electric utilities and fuel refineries increased slightly in 2011, according to the latest Toxics Release Inventory data from the U.S. Environmental Protection Agency.

Total on-site and off-site releases rose 4 percent, or about 101,000 pounds, in 2011 compared with 2010.

Toxic chemicals releases are categorized as on-site or off-site, and a total of 36 Hawaii facilities reported 2.6 million pounds of releases during 2011.

The Hawaii data also showed that from 2010:

>> Release of toxic chemicals into the air increased 6 percent or 106,000 pounds.

>> Release into water decreased 10 percent or 43,000 pounds.

>> On-site land releases decreased 27 percent or 47,000 pounds.

>> Underground injection releases increased 43 percent or 1,000 pounds.

The 10 facilities managing, treating or releasing the most toxic chemicals into the environment were Hawaiian Electric Co. at Kahe Point, Joint Base Pearl Harbor-Hickam, Chevron Products Co. Hawaii Refinery, AES Hawaii Inc., Hawaiian Electric Co. at Waiau, Maui Electric Co. in Kahului, Tesoro Hawaii Refinery, Hawaii Electric Light Co. in Hilo, the Maui Electric Co. in Maalaea, and the Hawaii Electric Light Co. in Keeau, the agency said.

The top toxic chemical was sulfuric acid, a byproduct of burning diesel fuel for power plants, followed by nitrate compounds, found in wastewater.

Hawaii EPA spokesman Dean Higuchi said the information was not enough to tell whether exposure of these chemicals on the environment and people increased.

Many of the facilities using toxic chemicals, including refineries and power plants, are required to reduce or dispose of pollutants before they enter the environment, he said.

Higuchi said the information is provided to help the public track the management, treatment and release of toxic chemicals nationwide.

The annual Toxic Release Inventory reporting began in 1988 after the enactment of the Emergency Planning and Community Right-to-Know Act of 1986.

The chemical information in the inventory is calculated by industrial facilities and reported to the EPA.

More information from the EPA is available online at www.epa.gov/region09/toxic/tri/; or www.epa.gov/triexplorer/statefactsheet.htm.