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Government and Industry Collaborate on Mercury Emissions Monitoring

Release Date: 4/12/2005
Contact Information: Bonnie Smith, 215-814-5543 & Maria Taylor at DNREC, 302-739-4506

Bonnie Smith, 215-814-5543 & Maria Taylor at DNREC, 302-739-4506

PHILADELPHIA – The U.S. Environmental Protection Agency and the Delaware Department of Natural Resources and Environmental Control have signed an agreement with Occidental Chemical Corporation (OxyChem) in which the company will voluntarily measure and reduce fugitive mercury emissions at its Delaware City plant.

OxyChem Delaware is one of nine mercury cell chlor-alkali facilities in the country producing chlorine gas, which is used widely in products for homes, industry, and medicine. Facilities obtain permits for releasing a limited amount of emissions into the air, usually through stacks or vents. Fugitive emissions are those which escape from plant equipment rather than being emitted through stacks or vents.

OxyChem approached DNREC and EPA to discuss a new methodology it wants to undertake to appropriately measure and reduce fugitive emissions. The company has invested in a first-of-its-kind technology for mercury monitoring.

“By conducting comprehensive, real-time localized monitoring there will be more information about this important issue and a better understanding of how fugitive mercury emissions escape and ways to reduce them,” said Donald S. Welsh, EPA mid-Atlantic regional administrator.

“We are committed to reducing mercury emissions in Delaware,” said DNREC Secretary John A. Hughes. “Collecting this information will enable the plant to continue identifying ways to further reduce emissions and allow us to make more informed decisions on further controlling mercury in the future. We are encouraged by OxyChem’s willingness to take these actions.”

The mercury monitoring system OxyChem is using is supplied by Mercury Instruments,
GmbH, Germany. An integral part of the year-long monitoring will be to continually evaluate opportunities for emissions reductions that can be implemented quickly. The recently installed monitoring system enables facility personnel to quickly identify, isolate and correct abnormal operating conditions in the facility’s main process building.

As an example, the monitor has detected elevated emissions that were due to minor equipment problems with pumps and heat exchangers. Workers were able to quickly identify the minor source, then repair the emission source, eliminating the emissions. In another instance the monitoring equipment identified an emissions source at a heat exchanger where the plant was able to modify plant procedures eliminating the need to service equipment that might have been a source of emissions, thereby reducing the emissions potential from future events.

Fugitive emissions of mercury from the facility are currently estimated based on calculations and modeling and reported to EPA and DNREC as part of the annual Toxic Release Inventory. For 2003 (the most recent data reported) the facility estimated 747 pounds of fugitive mercury emissions. The facility reported 1046 pounds of fugitive emissions in 2002. The monitoring equipment will measure actual fugitive emissions on a continuous basis and provide a more reliable and accurate source of information.

Under the agreement, the company will share all data with EPA and DNREC and will not make any claims of business confidentiality with respect to the monitoring data. Nationally, EPA has planned two monitoring studies to better quantify fugitive emissions at two other chlor-alkali facilities. Although not part of the national study, the information gained from the voluntary industry project in Delaware will be of interest to the national study.

EPA’s monitoring study is part of the agency’s effort to quantify how much mercury might be emitted from chlor-alkali plants as fugitive emissions. These studies will help the agency address mercury used in these facilities that is neither accounted for by emissions from stacks nor through reclamation. The agency’s best information to date indicates that a high level of fugitive emissions is unlikely, however, the monitoring studies will help EPA better understand this issue.

The OxyChem activities in the agreement announced today are voluntary, and not currently required under federal or state regulations. The agreement does not give the company reduced inspection priority or any leniency in environmental compliance. Recently, OxyChem has been inspected by DNREC and found in compliance with environmental regulations. OxyChem is also successfully undertaking a cleanup of historic pollution at the facility under a Resource Conservation and Recovery Act corrective action which is described on EPA’s website

The agreement is posted in the Hot Topics section of DNREC’s home page It can also be accessed directly at