House Stimulus Bill -- Regulatory Follies

I have downloaded the House Bill, H.R. 1 -- the American Recovery and Reinvestment Act of 2009, and will start going through it to analyze the innumerable regulatory follies contained in it. Some of these may never survive in negotiations with the Senate, but many are likely to be adopted. I will focus on single follies in each post. This one will discuss the provision requiring public works to use iron and steel produced in the US, even if it costs 25% more than imports. Thus the Bill provides:

SEC. 1110. USE OF AMERICAN IRON AND STEEL.
(a) IN GENERAL.—None of the funds appropriated
or otherwise made available by this Act may be used for
a project for the construction, alteration, maintenance, or
repair of a public building or public work unless all of the
iron and steel used in the project is produced in the United
States.
(b) EXCEPTIONS.—Subsection (a) shall not apply in
any case in which the head of the Federal department or
agency involved finds that—
(1) applying subsection (a) would be incon-
sistent with the public interest;
(2) iron and steel are not produced in the
United States in sufficient and reasonably available
quantities and of a satisfactory quality; or
(3) inclusion of iron and steel produced in the
United States will increase the cost of the overall
project by more than 25 percent.

Is this a sop to the steel unions? How many billions will this increase the cost of public works created under the program.