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                                                                    EXHIBIT 99.a

[ONEOK LOGO] 

                                 FINANCIAL NEWS
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ONEOK, INC.                                 CONTACT: WELDON WATSON, 918/588-7158
P.O. BOX 87
TULSA, OK 74102-0871                    FOR IMMEDIATE RELEASE: FEBRUARY 22, 1999


                   ONEOK CONFIRMS ITS OFFER FOR SOUTHWEST GAS 


         TULSA, Oklahoma -- ONEOK, Inc., has been advised by Southwest Gas
Corporation (NYSE:SWX) that it has received an unsolicited offer of $32 per
share of common stock from the Southern Union Company (NYSE:SUG). The ONEOK and
Southwest boards of directors unanimously approved a definitive agreement on
December 14, 1998, containing a cash offer by ONEOK of $28.50 for each
outstanding share of Southwest Gas common stock.

         Larry Brummett, ONEOK chairman and chief executive officer, said,
"Obviously, we were surprised by the Southern Union offer. We based our offer on
due diligence, consultation with investment advisors and sound business
judgment. We believe our offer is fair, competitive and still valid."

         The ONEOK offer would create the largest stand-alone gas distribution
company in the United States serving 2.6 million customers in five states. The
combined companies would become the primary gas distributor in Arizona, Kansas,
Nevada and Oklahoma with a strong presence in California.

         A ONEOK/Southwest Gas combination would be solid financially with
strong cash flow to enhance growth opportunities in the rapidly expanding
Southwest Gas service area. It would be a strong regional energy company poised
to compete in the rapidly deregulating energy marketplace better serving
shareholders, customers and employees.

         ONEOK (NYSE:OKE) is engaged in natural gas intrastate distribution and
transmission, gas processing, marketing and production. ONEOK has approximately
31.6 million shares of common stock outstanding.

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