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           SOUTHWESTERN ANNOUNCES SALE OF MISSOURI UTILITY PROPERTIES
       Sale Strengthens Focus on Adding Value From Core Areas of Operation

         FAYETTEVILLE, ARKANSAS - October 19, 1999...Southwestern Energy Company
(NYSE:  SWN) announced  today that it has signed a definitive  agreement to sell
its Missouri gas distribution assets to Atmos Energy Corporation (NYSE: ATO) for
$32.0  million.  The  transaction  is subject to  regulatory  approval  from the
Missouri Public Service Commission and the Federal Energy Regulatory  Commission
and compliance with the Hart-Scott-Rodino Act.

         The  Missouri  assets  are  part  of  Associated  Natural  Gas  Company
(Associated),   a  division  of  Arkansas  Western  Gas  Company,   which  is  a
wholly-owned  subsidiary of  Southwestern.  In Missouri,  Associated  employs 91
people and serves  approximately  48,000 residential,  commercial and industrial
customers,  primarily located near the towns of Sikeston, Kirksville, Butler and
Jackson.  Arkansas Western Gas Company serves approximately 131,000 customers in
Arkansas  and will  continue  to own and  operate  Associated's  assets that are
located in that state.

         "The sale of our  Missouri  utility  properties  is part of our ongoing
strategy  to  focus  our  efforts  in  core  operating  areas  where  we  have a
competitive advantage.  In addition,  this transaction will reduce our long-term
debt and strengthen our capital  structure," stated Harold M. Korell,  President
and Chief Executive Officer of Southwestern. "We are grateful for the dedication
and hard work of all our Associated employees and want to express special thanks
to our Missouri employees that will now become a part of Atmos."

         "This  transaction  is  consistent  with  Atmos'  long-term   corporate
development  strategy of increasing the value of the Company  through  strategic
acquisitions,"  said Robert W. Best,  Chairman,  President  and Chief  Executive
Officer of Atmos Energy  Corporation.  "The  addition of  Southwestern  Energy's
48,000  customers in Missouri  increases our presence in that state and provides
economies of scale which will result in a greater competitive advantage."

         Southwestern  Energy Company is an integrated natural gas company whose
wholly-owned subsidiaries are engaged in gas and oil exploration and production,
natural  gas   gathering,   transmission,   and   marketing,   and  natural  gas
distribution. Additional information on the Company can be found on the Internet
at http://www.swn.com.
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