Petrohawk Energy And KCS Energy Agree to Merge Creating $3.7 Billion Enterprise; Strategic Combination Creates Significant Onsh

Petrohawk Energy Corporation (NASDAQ: HAWK)
("Petrohawk") and KCS Energy, Inc. (NYSE: KCS) ("KCS") today announced
that they have entered into a definitive agreement to merge the
companies and create a leading onshore oil and gas producer with an
enterprise value of approximately $3.7 billion. The combined company
will continue to be known as Petrohawk Energy Corporation (the
"Company") and will be headquartered in Houston, Texas. On a pro forma
basis, the Company will have estimated proved reserves of
approximately one trillion cubic feet of natural gas equivalents
(Tcfe) of which approximately 68% would be classified as proved
developed and approximately 82% would be natural gas.
   Under the terms of the agreement, KCS stockholders will receive
$9.00 per share in cash and 1.65 shares of Petrohawk common stock for
each share of KCS common stock they own. This represents consideration
to KCS stockholders of $31.41 per share based on the closing price of
Petrohawk shares on April 20, 2006. Following the transaction, KCS
stockholders will own approximately 50% of the combined company.
   The transaction positions Petrohawk as one of the top independent
exploration and production companies in the U.S. The combination will
also create one of the most concentrated and high impact set of
domestic oil and natural gas assets amongst independent E&P companies,
primarily focused in the east Texas / north Louisiana, onshore Gulf
Coast, Permian and Anadarko / Arkoma regions.
   Floyd Wilson will continue his role as the Company's Chairman,
President and CEO. KCS's James Christmas will serve as Vice Chairman
and William Hahne as Executive Vice President and Chief Operating
Officer of the combined company. Following the completion of the
merger, the Company will have nine directors, five nominated by
Petrohawk, including Floyd Wilson, and four nominated by KCS,
including James Christmas.
   "The asset quality and fit derived from this transaction are
unparalleled in my experience," stated Floyd C. Wilson, Chairman,
President, and Chief Executive Officer of Petrohawk. "KCS is a proven
operator; and we believe our combined properties have extraordinary
development and exploration potential. We feel the collective staff of
Petrohawk and KCS is uniquely qualified to create value from the
tremendous upside potential inherent to both companies. Jim Christmas
will be Vice Chairman and continue to play a key role in the Company.
In addition, we hope to retain the majority of the talented KCS staff.
This combination creates the company we originally set out to build."
   "We have been impressed by the job that Floyd Wilson and his team
have done in building Petrohawk to its current position in very short
order through a series of high quality, strategic acquisitions that
have made it a formidable competitor in the areas we operate. By
combining KCS, which has grown rapidly through drilling, and
Petrohawk, we are creating an even stronger company with proved oil
and gas reserves of nearly 1 Tcfe, current daily production of over
290 Mmcfe and very significant additional potential in our core
operating areas," said James W. Christmas, Chairman and Chief
Executive Officer of KCS. "We believe that this combination not only
delivers immediate value to the stockholders of both companies, but
also creates a company well positioned to deliver above average growth
in value going forward."
   Petrohawk, a company grown primarily through strategic
acquisitions, and KCS, which has grown predominantly through
successful exploration and development activities, are expected to
utilize expertise from each company to realize the substantial upside
potential within the combined portfolio.

   Combination Rationale:

   --  Creates a leading independent onshore producer which on a
        combined basis possesses nearly 1 Tcfe of proven reserves,
        current production of 291 million cubic feet equivalent per
        day and an enterprise value of approximately $3.7 billion

   --  Unites experienced technical staffs to enhance the development
        and exploration potential from a virtual overlay of core
        operating areas

   --  Combined position in the Elm Grove and Caspiana fields
        represents a premier, operated core asset in the fast growing
        north Louisiana natural gas basin

   --  Immediate accretion to cash flow, production and NAV on a per
        share basis

   --  Pro forma capital budget of $525 million exposes the Company
        to a prolific set of drilling opportunities

   --  Combined asset base includes over 4,000 identified non-proved
        drilling locations, as well as approximately 900 proved
        drilling locations

   --  The Company will have over 2 Tcfe of additional resource
        potential

   Pro Forma Statistics:

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                                                                 Pro
                                            Petrohawk   KCS      Forma

Proved Reserves (Bcfe)
at December 31, 2005(a)                        517      463       980

Proved Developed                                64%      73%       68%

Natural Gas                                     76%      88%       82%

Operated (based on reserves)                    60%      86%       74%

Estimated Current Production (Mmcfe/d)         135      156       291

R/P (years)                                   10.5      8.2       9.2
*T

   (a)Petrohawk reserves include approximately 106 Bcfe of
internally-estimated reserves associated with a recently closed north
Louisiana acquisition. KCS reserves include internally estimated 11
Bcfe of reserves for another recently closed north Louisiana
acquisition.
   Netherland, Sewell and Associates, Inc., an independent reserve
engineering firm, prepares Petrohawk's and audits KCS's estimated
proved reserves.

   Combined Capital Budget:

   The combined capital program for 2006 represents record activity
levels in core operating areas and includes over 500 planned wells,
including over 200 non-proved locations.
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Pro Forma 2006 Capital Expenditure Budget ($ millions):

                                    HAWK      KCS     Pro Forma     %
                               ---------------------------------------
East Texas / North Louisiana         $51     $158        $209      40
Onshore Gulf Coast                   110       88         198      38
Permian                               18       41          59      11
Anadarko / Arkoma                     31       28          58      11
                               ---------------------------------------
Total                               $210     $315        $525     100
*T

   Merger Agreement:

   Pursuant to the terms of the agreement, KCS stockholders will
receive $9.00 per share in cash and 1.65 shares of Petrohawk common
stock for each share of KCS common stock they own, or collectively
$450 million in cash and approximately 84 million Petrohawk common
shares, not including outstanding KCS stock options. KCS stock options
will convert into Petrohawk options pursuant to the terms of the
merger agreement.
   The transaction is subject to the approval of the stockholders of
Petrohawk and KCS. The boards of directors of both companies have
unanimously approved the merger agreement, which is subject to
customary conditions, including approval of listing of the Petrohawk
shares to be issued in the merger on NASDAQ and regulatory approvals.
The transaction is expected to be completed during the third quarter
of 2006.
   Harris Nesbitt acted as financial advisor, Hinkle Elkouri Law Firm
LLC and Thompson & Knight LLP acted as legal advisors and Petrie
Parkman provided a fairness opinion for Petrohawk. Morgan Stanley
acted as exclusive financial advisor and rendered a fairness opinion
to KCS in connection with the transaction. Andrews Kurth LLP acted as
legal advisor and Griffis & Associates, LLC acted as technical advisor
to KCS.

   Investor Conference Call:

   Petrohawk and KCS will host a joint conference call on April 21,
2006 to discuss the proposed transaction at 9:00 a.m. EDT, 8:00 a.m.
CDT. Investors may participate in the conference call by telephone
dialing 800-644-8607 a few minutes before the call begins and asking
for the Petrohawk Energy / KCS Energy conference call, conference ID
8373063. International callers may also participate by dialing
706-679-8184. A replay of the conference call will be available
approximately two hours after the end of the call until April 28,
2006. To access the replay, dial 800-642-1687 and reference conference
ID 8373063. International callers may listen to a playback by dialing
706-645-9291.

   Petrohawk Energy Corporation is an independent energy company
engaged in the acquisition, production, exploration and development of
oil and gas, with properties concentrated in the South Texas,
Mid-Continent, East Texas, North Louisiana, Arkoma, Permian and Gulf
Coast regions.

   KCS is an independent energy company engaged in the acquisition,
exploration, development and production of natural gas and crude oil
with operations in the Mid-Continent and Gulf Coast regions.

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For more information please refer to the companies' websites or
contact:

For Petrohawk:

Shane M. Bayless                            Joan Dunlap
[phone]                              [phone] 
[e-mail]                      [e-mail]

For KCS Energy:
Jim Christmas
[phone]
[e-mail]
*T

   Additional Information for Investors

   This press release contains "forward-looking statements" within
the meaning of the US Private Securities Litigation Reform Act of
1995, based on Petrohawk's and KCS's current expectations and include
statements regarding planned capital expenditures (including the
amount and nature thereof), timing for proposed acquisitions and
divestitures, estimates of future production, statements regarding
business plans and timing for drilling and exploration expenditures,
the number of wells both companies anticipate drilling in 2006, the
number and nature of potential drilling locations, future results of
operations, quality and nature of the combined asset base, the
assumptions upon which estimates are based and other expectations,
beliefs, plans, objectives, assumptions, strategies or statements
about future events or performance (often, but not always, using words
such as "expects", "anticipates", "plans", "estimates", "potential",
"possible", "probable", or "intends", or stating that certain actions,
events or results "may", "will", "should", or "could" be taken, occur
or be achieved). Statements concerning oil and gas reserves also may
be deemed to be forward looking statements in that they reflect
estimates based on certain assumptions that the resources involved can
be economically exploited. Forward-looking statements are based on
current expectations, estimates and projections that involve a number
of risks and uncertainties, which could cause actual results to differ
materially from those, reflected in the statements. These risks
include, but are not limited to: the possibility that the companies
may be unable to obtain stockholder or other approvals required for
the acquisition; the possibility that problems may arise in the
integration of the businesses of the two companies; the possibility
that the acquisition may involve unexpected costs; the possibility the
combined company may be unable to achieve cost-cutting objectives; the
risks of the oil and gas industry (for example, operational risks in
exploring for, developing and producing crude oil and natural gas;
risks and uncertainties involving geology of oil and gas deposits; the
uncertainty of reserve estimates; the uncertainty of estimates and
projections relating to future production, costs and expenses;
potential delays or changes in plans with respect to exploration or
development projects or capital expenditures; health, safety and
environmental risks and risks related to weather such as hurricanes
and other natural disasters); uncertainties as to the availability and
cost of financing; fluctuations in oil and gas prices; inability to
realize expected value from acquisitions, inability of our management
team to execute its plans to meet its goals, shortages of drilling
equipment, oil field personnel and services, unavailability of
gathering systems, pipelines and processing facilities and the
possibility that government policies may change or governmental
approvals may be delayed or withheld. Additional information on these
and other factors which could affect either companies' operations or
financial results are included in the companies' other reports on file
with the United States Securities and Exchange Commission.
Forward-looking statements are based on the estimates and opinions of
both companies' management at the time the statements are made.
Neither Petrohawk nor KCS assume any obligation to update
forward-looking statements should circumstances or management's
estimates or opinions change.

   Additional Information About the Transaction and Where to Find It:

   Petrohawk and KCS will file materials relating to the transaction
with the SEC, including one or more registration statement(s) that
contain a prospectus and a joint proxy statement. Investors and
security holders of Petrohawk and KCS are urged to read these
documents (if and when they become available) and any other relevant
documents filed with the SEC, as well as any amendments or supplements
to those documents, because they will contain important information
about Petrohawk, KCS and the transaction. Investors and security
holders may obtain these documents free of charge at the SEC's website
at www.sec.gov. In addition, the documents filed with the SEC by
Petrohawk may be obtained free of charge from Petrohawk's website at
www.petrohawk.com. The documents filed with the SEC by KCS may be
obtained free of charge from KCS's website at www.kcsenergy.com.
Investors and security holders are urged to read the joint proxy
statement/prospectus and the other relevant materials when they become
available before making any voting or investment decision with respect
to the proposed acquisition.
   Petrohawk, KCS and their respective executive officers and
directors may be deemed to be participants in the solicitation of
proxies from the stockholders of Petrohawk and KCS in favor of the
acquisition. Information about the executive officers and directors of
Petrohawk and their direct or indirect interests, by security holdings
or otherwise, in the acquisition will be set forth in the proxy
statement-prospectus relating to the acquisition when it becomes
available. Information about the executive officers and directors of
KCS and Petrohawk and their direct or indirect interests, by security
holdings or otherwise, in the acquisition will be set forth in the
proxy statement-prospectus relating to the acquisition when it becomes
available.