Oregon Steel Mills Announces Restart of Seamless Mill and New Joint Venture

Oregon Steel Mills, Inc. (NYSE:OS) announced today that
it will reopen the seamless mill (the "Mill") at its Rocky Mountain
Steel Mills plant in Pueblo, Colorado. The Mill, which has been idle
since November 2003, has an annual capacity of 150,000 tons, depending
on product mix, and can produce seamless casing, coupling stock, and
standard and line pipe. The Mill is equipped to produce tubular
products from 5-1/2 inches to 10-3/4 inches in diameter. The
production capability of the Mill includes both carbon and
heat-treated tubular products. Production is expected to begin in
December of 2005 at an annual rate of 100,000 tons with an emphasis on
quench and temper seamless casing products.
   In conjunction with the reopening of the Mill, the Company has
reached an agreement in principle with Colorado Seamless Corporation
("Colorado Seamless"), an affiliate of OCTG, L.L.P. ("OCTG") of
Houston, Texas, for Colorado Seamless to purchase all of the product
produced at the Mill. OCTG will perform full-length ultrasonic testing
on the Mill product as part of the manufacturing quality control
program. Colorado Seamless will ship the product to the OCTG facility
in Houston, where the remainder of the end-finishing process will take
place.
   Oregon Steel also announced today that it has entered into an
agreement with a Canadian investment group to construct a facility at
the Company's pipe mill located in Camrose, Alberta, Canada, to
manufacture, sell and service coiled tubing products. Coiled tubing is
a welded product produced in diameters from 1 inch through 3-1/2
inches and wrapped around a spool for continuous feed in oil and gas
field applications. Uses of coiled tubing include well completion,
well work over and clean out, well stimulation and logging, drilling
and production. It is anticipated that construction of the coiled
tubing facility will be completed in the first quarter of 2006. Oregon
Steel, through a subsidiary, will own 51 percent of the joint venture
and will be the managing partner. The joint venture, when operational,
will be the only manufacturer of coiled tubing products located in
Canada.
   Jim Declusin, the Company's President and CEO, stated, "We are
very excited about the reopening of the seamless mill and the coiled
tubing venture. The investments being made in these product lines will
enable us to offer more value-added specialty products that will
compliment our current offerings of energy-related products as well as
our specialty plate, rail and rod and bar products. With the startup
of the seamless and coiled tubing mills and the expected commissioning
of the new large diameter pipe mill in Portland, Oregon, in the first
quarter of 2006, we will have approximately 650,000 tons of production
capacity dedicated to the oil country tubular goods and line pipe
markets. As a result of today's energy prices, we anticipate that the
high level of exploration and production activity will continue and
should result in increased demand for all of our energy-related
products. Assuming that selling prices remain favorable, we expect the
energy part of our business to record strong financial performance
into the foreseeable future."

   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; cost and availability of
raw materials; 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
the Company's most recently filed Form 10-K, Form 10-Q and other SEC
reports.
   These forward-looking statements should not be relied upon as
representing the Company's views as of any subsequent date and the
Company undertakes no obligation to update or revise the
forward-looking statements, whether as a result of new information,
future events or otherwise, after the date they are made.

   Oregon Steel Mills, Inc. is organized into two divisions. The
Oregon Steel Division produces steel plate, coil, small and large
diameter line pipe, casing 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 and bar, and seamless tubular products.