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                            (O.I. CORPORATION LOGO)
       P.O. BOX 9010   COLLEGE STATION, TEXAS 77842-9010   (979) 690-1711
                               FAX: (979) 690-0440

                                                              Investor Relations
                                                     Bruce Lancaster / V.P., CFO

NEWS RELEASE

                           O.I. CORPORATION ANNOUNCES
                         RESULTS FOR FIRST QUARTER 2007

College Station, Texas, May 15, 2007 - O.I. Corporation (NASDAQ: OICO) today
reported results for the three months ending March 31, 2007.

FOR THE FIRST QUARTER ENDED MARCH 31, 2007

Revenue declined 6.0% to $7,342,000 for the first quarter of 2007, compared to
$7,809,000 for the same period of the prior year. The net loss for the quarter
totaled $362,000, compared to net income of $622,000 for the first quarter of
2006. O.I. recorded a diluted loss per share of $0.13 in the first quarter of
2007 compared to diluted earnings per share of $0.21 during the same period of
2006.

J. Bruce Lancaster, Vice President and Chief Financial Officer commented:

"We are very disappointed to report a quarterly loss for the first time in five
years. As we previously disclosed, costs incurred in connection with the stock
option investigation conducted during the first quarter totaled approximately
$1,250,000. This major expense negatively impacted our earnings for the quarter.

"In addition, we recorded service revenues of $408,000 during the first quarter
of 2006 associated with billings under the Wyle contract for development of a
Total Organic Carbon Analyzer for use on the International Space Station. This
contract was completed during 2006, so our 2007 service revenues declined in
comparison to last year, also reducing our 2007 earnings.

"After consideration of these unusual items, earnings from our core operations
were in line with those for the first fiscal quarter of 2006. Despite our loss
during this difficult quarter, we ended March in a very strong financial
position with $12,707,000 in cash and investments, total assets of $29,346,000
and equity of $23,651,000. I am pleased that our financial strength has allowed
us to continue our quarterly dividend to our shareholders and we will continue
to explore other means to improve shareholder value.

"In addition to the expense associated with the stock option investigation, this
process served as a distraction to both our management team and Board of
Directors. We look forward to focusing our resources on operational activities
in the months ahead."

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Dr. Don Segers, Acting President of O.I., noted:

"Our product revenues held steady during the first quarter, primarily because of
significant MINICAMS sales we shipped under an order to the U.S. Army during the
first quarter, completing the bulk of our commitment under the contract we
announced on May 17, 2006. Our higher sales in this product line offset lower
sales of products sold in the domestic environmental testing market. We continue
to see minimal growth in this area.

"Billings under the U.S. Army contract announced March 19 of this year for
development of an inexpensive Total Organic Carbon detector should commence
during the second quarter and favorably impact our service revenues over the
balance of the year.

"In looking to the future, we are developing new technologies in each of our
major product lines and remain optimistic about the potential for the mass
spectrometer technology we are developing based on ion-CCD detectors. While we
are confident the technologies we are developing will enhance future revenues,
these long-term projects are unlikely to culminate in revenue generating
products prior to 2009. During the interim period, the costs associated with
product development will continue to be reflected as R&D expense, which we
anticipate to remain at current levels.

"We are working to expand our organic growth opportunities and will also explore
prospective acquisitions that complement our existing product lines which assess
the quality of the air we breathe and the water we drink."

                                O.I. CORPORATION
                              FINANCIAL HIGHLIGHTS

<TABLE>
<CAPTION>
                                          Three Months Ended
                                               March 31
                                       -----------------------
                                          2007         2006
                                       ----------   ----------
<S>                                    <C>          <C>
Net revenues                           $7,342,000   $7,809,000
(Loss) income before income taxes      $ (464,000)  $  888,000
(Benefit) provision for income taxes   $ (102,000)  $  266,000
Net (loss) income                      $ (362,000)  $  622,000
Weighted average shares, basic          2,862,000    2,859,000
Basic (loss) earnings per share        $    (0.13)  $     0.22
Weighted average shares, diluted        2,862,000    2,940,000
Diluted (loss) earnings per share      $    (0.13)  $     0.21
</TABLE>

O.I. Corporation, dba OI Analytical, provides innovative products used for
chemical analysis. The Company develops, manufactures, sells, and services
analytical instrumentation that detects, measures, analyzes, and monitors
chemicals in liquids, solids, and gases. The Company provides products used to
digest, extract, and separate components of chemical mixtures. The Company
provides application-specific

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solutions for the environmental, defense, pharmaceutical, food, beverage,
petrochemical, chemical, semiconductor, power generation, and HVAC industries.
Headquartered in College Station, Texas, the Company's products are sold
worldwide by direct sales, independent sales representatives, and distributors.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS:

Statements in this release regarding expected future results are forward looking
statements that are subject to the Safe Harbor provisions created by the Private
Securities Litigation Reform Act of 1995. These forward looking statements are
based on current information and expectations, and involve a number of risks and
uncertainties. Actual results may differ materially from those projected in such
forward looking statements due to various factors, including but not limited to:
those factors detailed in our filings with the Securities and Exchange
Commission, including our Quarterly Report on Form 10-Q filed May 15, 2007 and
our Annual Report on Form 10-K filed April 2, 2007. Readers are cautioned not to
place undue reliance upon these forward looking statements, which speak only as
of the date hereof, and we undertake no obligation to update these forward
looking statements to reflect subsequent events or circumstances. The inclusion
of any statement in this release does not constitute an admission by the company
or any other person that the events or circumstances described in such statement
are material.

                   Visit the Company's worldwide web site at:
                               HTTP://WWW.OICO.COM