Oregon Steel Mills, Inc. Revises Second Quarter Outlook

Oregon Steel Mills, Inc. (NYSE:OS) today revised its
outlook for the second quarter. The Company had previously estimated
that its second quarter earnings per diluted share would be in the
range of $.85 to $.95. The Company now expects second quarter earnings
per diluted share to be in the range of $.75 to $.85. First quarter
2005 results were $.79 per diluted share.
   The lower expectation is primarily due to the inability to achieve
the scheduled delivery on approximately 30,000 tons of welded pipe
products representing approximately $34 million of revenue. The
delivery has been affected by 1) shortages of railroad cars and 2)
adverse weather conditions at the product destination points. The
product is expected to be delivered and the associated revenue
recognized during the third quarter of 2005.
   Jim Declusin, the Company's President and CEO, stated, "While
sales volume for the Company's plate and rod products have declined in
recent months due to customer inventory balances, operating margin per
ton for these products continues to compare favorably to those
realized in the first quarter of 2005. We expect demand for these
products to pick up in the third quarter as customer inventories are
reduced. Welded pipe and rail products continue to meet volume and
operating margin expectations. While total shipments of product for
2005 are expected to decline approximately 5 percent from 2004, the
Company believes that operating income from continuing operations for
2005 will be approximately the same as that realized in 2004, before
the 2004 labor dispute settlement charges."

   FORWARD-LOOKING STATEMENTS

   Forward-looking statements in this release are made pursuant to
the safe harbor provisions of the Private Securities Litigation Reform
Act of 1995. Such forward-looking statements are subject to risks and
uncertainties and actual results could differ materially from those
projected. Such risks and uncertainties include, but are not limited
to, general business and economic conditions; competitive products and
pricing, as well as fluctuations in demand; potential equipment
malfunction, and plant construction and repair delays. For more
detailed information, please review the discussion of risks, which may
cause results to differ materially, in our most recently filed Form
10-K, Form 10-Q and other SEC reports.
   Oregon Steel Mills, Inc. is organized into two divisions. The
Oregon Steel Division produces steel plate, coil, welded pipe and
structural tubing from plants located in Portland, Oregon and Camrose,
Alberta, Canada. The Rocky Mountain Steel Mills Division, located in
Pueblo, Colorado, produces steel rail, rod, bar, and tubular products.