<PAGE>

                                                                    Exhibit 10.8

                      EMPLOYMENT/NON-COMPETITION AGREEMENT

            THIS AGREEMENT, is made and entered into this 1st day of May, 2000,
by and between A. M. CASTLE & CO., a Delaware corporation, with offices located
at 3400 North Wolf Road, Franklin Park, Illinois 60131 (the "Company") and G.
THOMAS McKANE who resides at Unit 21 AD, 421 West Monroe Street, Chicago,
Illinois 60657 ("Executive").

            WHEREAS, the Company desires to employ Executive and Executive
desires to be employed by the Company, all upon the terms and conditions set
forth herein.

            NOW, THEREFORE, in consideration of the mutual agreements herein set
forth, the parties agree as follows:

            1.    Employment. The Company hereby employs the Executive, and the
Executive hereby accepts such employment with the Company, upon all the terms
and conditions set forth below. Executive represents and warrants that he has
full power and authority to enter into this Employment Agreement and that he is
not restricted in any manner whatsoever from performing his duties hereunder.

            2.    Employment Term. Unless earlier terminated as hereinafter
provided, the term of the Executive's employment under this Agreement shall
commence on the date it is fully executed by all parties and shall continue from
year to year until terminated as hereinafter provided ("Employment Term").

            EXCEPT AS OTHERWISE PROVIDED IN THIS AGREEMENT, THE COMPANY AND THE
EXECUTIVE ACKNOWLEDGE THAT THE EXECUTIVE'S EMPLOYMENT IS AT WILL AND CAN BE
TERMINATED BY EITHER PARTY AT ANY TIME WITH OR WITHOUT CAUSE: If the Executive's
employment terminates for any reason, with or without cause, the Executive shall
not be entitled to any payments, benefits, damages, awards or compensation other
than as provided in this Agreement.

            3.    Position and Duties.

                  a.    Chief Executive Officer. The Company shall employ the
      Executive in the position of and with the titles of President and Chief
      Executive Officer. Executive shall have the responsibilities and duties as
      are commensurate with the position of president and chief executive
      officer of an entity comparable to the Company including, but not limited
      to, the powers and duties set forth in the Bylaws of the Company for such
      office. Executive shall report to the Company's Board of Directors. The
      Board of Directors of the Company ("Board") may assign other duties and
      rights to Executive from time to time. The Board shall have the right to
      modify the responsibilities of the Executive from time to time as the
      Board may deem necessary or appropriate. Executive shall be provided with
      an office, secretarial services, and other services commensurate with the
      status of his position.

                  b.    Manner of Employment. Executive shall faithfully,
      diligently and competently perform his responsibilities and duties as
      President and Chief Executive Officer. The Executive shall devote his
      exclusive and full efforts and time to the Company. This Section 3,
      however, shall not preclude the Executive, from, with prior approval from
      the Board, serving as a member of the board of directors of another
      company, or outside normal business hours, from engaging in appropriate
      civic or charitable activities, as long as such activities do not
      interfere or conflict with his responsibilities to the Company.

                  c.    Board of Directors. Subject to approval by the
      shareholders of the Company, the Company agrees to take all corporate
      actions necessary for the appointment or election of the Executive to the
      Board of Directors within a reasonable period of time from the date of
      this Agreement. If elected to the Board of Directors of the Company,
      Executive shall have all the duties and responsibilities as are
      commensurate with the position of director. However, Executive shall
      receive no additional compensation as a director of the Company.

            4.    Compensation.

                  a.    Base Compensation. The Company shall pay the Executive
      as compensation for his services a base compensation in the amount of Four
      Hundred Thousand Dollars ($400,000) per year subject to annual reviews and
      increases at the sole discretion of the Board ("Base Compensation"). Base,
      Compensation shall be paid periodically in accordance with normal Company
      payroll practices.

                  b.    Additional Compensation. The Executive shall participate
      in the management incentive/bonus plan established by the Company for
      management and executive employees. The Executive's participation shall
      provide for a maximum incentive equal to One Hundred percent (100%) of his
      Base Compensation.

                  Furthermore, with respect to calendar year 2000, Executive's
      incentive compensation shall be guaranteed to be not less than Two Hundred
      Thousand Dollars

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                                                                    Exhibit 10.8

      ($200,000).

                  c.    Stock Options. The Executive shall be granted stock
      options in the amount of Two Hundred Thousand (200,000) shares for the
      year 2000. The option price shall be the closing price of the Company's
      common stock on the date of the granting of the option by the Board of
      Directors which shall be the business day prior to the public announcement
      of the Agreement. The Executive shall be given annual stock options
      thereafter in an amount to be determined by the Human Resources Committee
      of the Board of Directors.

                  d.    Restricted Stock. The Executive shall be awarded
      restricted common stock in the amount of One Hundred Thousand (100,000)
      shares. The restricted stock price shall be the closing stock price on the
      business day preceding the public announcement of the Agreement. The
      restricted common stock shall vest Fifty percent (50%) at the end of the
      first year of employment and Twenty Five percent (25%) at the end of each
      year of employment thereafter for the next two (2) years.

                  e.    The grants of stock options and restricted stock options
      shall be made in accordance with the 1996 Restricted Stock and Stock
      Option Plan approved by the Company's stockholders on April 26, 1996.

            5.    Employment Benefits. In addition, Executive shall be entitled
to the following benefits during the Employment Term.

                  a.    Four (4) weeks paid vacation per calendar year to be
      taken at such reasonable times as requested by the Executive.

                  b.    Reimbursement for reasonable out-of-pocket business
      expenses incurred by Executive during the regular performance of his
      duties for the Company, provided Executive provides the Company with
      adequate documentation of such expenses in accordance with the Company's
      policies.

                  c.    Participation in any insurance or other employee benefit
      plans or programs maintained by the Company for its employees or
      substantially the same terms and conditions as such benefits are provided
      or made available to management employees of the Company, such as family
      health care and 401(k) plans.

                  d.    Use of a Company automobile at a class or level
      consistent with that provided by the Executive's prior employer
      immediately before joining the Company.

                  e.    Payment by the Company on behalf of Executive of the
dues and assessments of membership at a country club of his choice.

            Eligibility and entitlement for all benefits shall be subject, in
each case, to the generally applicable terms and conditions contained in plan
documents (where applicable) and the Company's policies and practices regarding
such benefits.

            6.    Termination and Severance Benefits.

                  a.    Death. The death of Executive shall automatically
      terminate the Company's obligations hereunder, provided however, the
      Company shall pay to Executive's estate Executive's Base Compensation,
      Management Incentive/Bonus (pro-rata in accordance with and at the payment
      date provided in the Company's Management Incentive Plan) and accrued
      vacation pay through the date of termination.

                  b.    Disability. If Executive is unable to render services of
      substantially the kind and nature, and to substantially the extent,
      required to be rendered by Executive hereunder due to illness, injury,
      physical or mental incapacity or other disability, for sixty (60)
      consecutive days or shorter periods aggregating at least one hundred
      eighty (180) days within any twelve (12) month period, Executive's
      employment may be terminated by Company and Executive shall be entitled to
      Base Compensation, Management Incentive/Bonus (pro-rata in accordance with
      and at the payment date provided in the Company's . Management Incentive
      Plan) and accrued vacation pay through the date of termination.

                  c.    Resignation. If Executive resigns his employment during
      the Employment Term, the Company shall have no liability under this
      Agreement, except as may be specifically provided for in Company plans in
      cases of resignation, to Executive except to pay Executive Base
      Compensation and any accrued but unused vacation pay through his last day
      worked and Executive shall not be entitled to receive severance or other
      benefits.

                  d.    Termination by Company for Cause. The Company may
      terminate the Executive for Cause upon giving sixty (60) days written
      notice to the Executive. Any such written notice must specify the reasons
      for the termination. If the Executive's employment is terminated

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                                                                    Exhibit 10.8

      for Cause, as defined herein, the Company shall have no liability under
      this Agreement to Executive except to pay Executive Base Compensation and
      any accrued but unused vacation pay through his last day worked and
      Executive shall not be entitled to receive severance or other benefits.

                  e.    Termination bpi Company Without Cause. If the Company
      terminates Executive's employment effective during the Employment Term
      without Cause (as defined herein), Executive shall be entitled to receive
      his Base Compensation for the remainder of the Employment Term or the sum
      of Eight Hundred Thousand Dollars ($800,000) whichever is greater. Such
      sum shall, be payable monthly or in one lump sum at the sole election of
      Executive within thirty (30) days after the Termination Date.

                        (1)   In addition, Executive shall have the right to
            receive all vested restricted common stock and shall have Ninety
            (90) days after the Date of Termination in which to exercise all
            vested Stock Options.

                  f.    Notice of Termination. Any purported termination of
      Executive's employment by the Company or by Executive (other than by
      reason of death) shall be effectively communicated to the other party by
      written notice identifying the effective date of termination and the
      reason or cause for termination.

                  g.    The following acts by Executive shall constitute "Cause"
      for termination.

                        (1)   Willful theft or embezzlement, or willful
      attempted theft or embezzlement, of money or intangible assets or property
      of Company;

                        (2)   Any willful act knowingly committed that subjects
            the Company or any officer of the Company to any criminal liability
            for such act;

                        (3)   Conviction of a felony involving moral turpitude;

                        (4)   Gross and willful misconduct by Executive that
            results in a material injury to the Company;

                        (5)   A finding of willful dishonesty of Executive that
            results in a material injury to the Company;

                        (6)   Willful malfeasance by Executive, provided that
            such malfeasance in fact has an injurious effect on the Company; and

                        (7)   Willful insubordination or willful refusal to
            perform assigned duties provided that Executive shall have an
            opportunity of thirty (30) days to cure any such act or failure to
            act.

                        (8)   Executive's material breach of this Agreement.

                  h.    Change of Control. In the event of a Change of Control
      (as defined below), Executive shall be entitled to the benefits as
      described under section 6(e), Termination by Company Without Cause, if any
      of the following occurs:

                        (1)   Executive is Terminated without Cause within the
            first twelve (12) months following the Change of Control;

                        (2)   Executive voluntarily resigns after Executive's
            title, role, duties, compensation or responsibilities within the
            Company are materially changed or reduced within the first twelve
            (12) months following the Change of Control, provided Executive must
            provide the Company notice of his intent to resign under this
            section 6(h).

                  Provided further that, during the first twelve (12) months
      following such Change of Control, or any material change in Executive's
      title, role, duties, compensation, or responsibilities shall result in a
      one hundred percent (100%) acceleration of Executive's vesting schedule
      and Executive shall have the remaining life of the original option term to
      exercise such options, notwithstanding any provisions of any stock option
      agreement to the contrary.

                  "Change of Control" shall mean the acquisition by any
      individual or business entity ("Person") of-beneficial ownership of more
      than fifty percent (50%) of the equity or voting power of the Company,
      excluding any acquisition by the Company or any Company employee benefit
      or trust.

            7.    Confidential and Proprietary Information.

                  a.    Executive covenants that after the date of this
      Agreement, he will not use or disclose to any person, entity, association,
      firm or corporation, without the written authorization of the Board, any
      of the Company's Confidential Information. The term "Confidential
      Information" means information and data not generally known outside the
      Company (unless a result of a breach of any of the obligations imposed by
      this Agreement or the wrongful conduct of any third party) concerning the
      Company's business and technical information, and includes, without

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                                                                    Exhibit 10.8

      limitation, information relating to: (i) the identities of its customers
      and their purchasing habits, needs, credit histories, contact personnel
      and other information; (ii) suppliers' and vendors' costs, products,
      discounts, margins, contact personnel and other information; and (iii) the
      Company's trade secrets, price lists, margins, discounts, financial and
      marketing information, personnel and compensation information, business
      plans and operating procedures and techniques.

                        Executive understands that this Section 7 applies to
      computerized as well as written information and to other information,
      whether or not in written form. It is expressly understood, however, that
      the obligations of this Section 7 shall only apply for as long as and to
      the extent that the Confidential Information has not become generally
      known to or available for use by the public other than by Executive's
      wrongful act or omission or the wrongful act of any third party.

                  b.    Executive covenants that at the end of his employment
      (regardless of the reason for termination) with the Company he will not
      take with him any Confidential Information that is written, computerized,
      machine readable, model, sample or other form capable of physical
      delivery, without the prior written consent of the Company. The Executive
      also agrees that at the end for any reason of his employment with the
      Company or at any other time that the Company may request, he will deliver
      promptly and return to the Company all such documents and materials in his
      possession or control, along with all other property of the Company and
      property relating to the Company's suppliers, customers and business.

                  c.    Executive agrees that all inventions, innovations,
      improvements, developments, methods, designs, analyses, drawings, reports
      and all similar or related information which relates to the Company or any
      of its Subsidiaries' actual or anticipated business, research and
      development of existing or future products or services (including new
      contributions, improvements, ideas and discoveries, whether patentable or
      not) and which are conceived, developed or made by Executive while
      employed by the Company ("Work Product") belong to the Company or such
      Subsidiary. Executive will promptly disclose such Work Product to the
      Board and perform all actions reasonably requested by the Board to
      establish and confirm such ownership. All work shall be deemed work made
      for hire. For purposes of this Agreement the term "Subsidiary" means any
      corporation or other entity of which the securities having a majority of
      the voting power in electing directors or similar persons are, at the time
      of determination, owned by the Company, directly or through one or more
      subsidiaries. Notwithstanding the foregoing, this Section 7(c) shall not
      apply to an invention that Executive developed entirely on his own time
      without using the Company's equipment, supplies, facilities or trade
      secret information except for those inventions that either (i) relate at
      the time of conception or reduction to practice of the invention to the
      Company's business, or actual or demonstrably anticipated research or
      development of the Company; or (ii) result from any work performed by
      Executive for the Company.

            8.    Non-Compete. The Executive and the Company agree that the
Company's business will be national in scope and depends, to a considerable
extent, upon the individual efforts of the Executive in sales, marketing and
management. . Further, the Company and Executive recognize that in the course of
Executive's employment with the Company, Executive has had and will continue to
have access to substantial amount of confidential and proprietary information
and trade secrets relating to the business of the Company, and that it would be
detrimental to the business of the Company, and have a substantial detrimental
effect on the value of the Company and Executive's employment if Executive were
to compete with the Company upon termination of his employment. Executive
therefore agrees, in consideration of the Company entering this Agreement,
establishing the base annual compensation and other compensation benefits at the
level herein provided for, that during the period of the term of his employment
with the Company, whether pursuant to this Agreement or otherwise, and
continuing for the lesser of (i) a period of two (2) years thereafter; or (ii)
the longest period permitted by applicable law (such period referred to herein
as the "Restricted Period"), he shall not, without the prior written consent of
the Company, directly or indirectly, either for himself or for any other person
or entity:

                  a.    Anywhere in the continental United States of America in
      which the Company has been conducting, or intends to conduct business,
      engage or participate in, or assist, advise or be connected with
      (including as an owner, partner, shareholder, advisor, consultant, agent
      or (without limitation by the specific enumeration of the foregoing) or
      otherwise, or permit his name to be used by or render services for, any
      person or entity engaged in, or making plans to engage in, a business
      which is competitive with, or substantially similar to, the Company's
      business (a "Competing Business"); provided, however, that nothing in this
      Agreement shall

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                                                                    Exhibit 10.8

      prevent Executive from acquiring or owning, as a passive investment, up to
      two percent (2 degrees/D) of the outstanding voting securities of an
      entity, in the aggregate, engaged in a Competing Business which are
      publicly traded in any recognized national securities market;

                  b.    Take any action which might divert from the Company any
      opportunity (each, an "Opportunity") which would be within the scope of
      the Company's business, and shall offer each Opportunity to the Company
      which the Company may, in its sole discretion, decide to pursue or not;

                  c.    Solicit, attempt to solicit, aid in the solicitation of,
      or accept any orders from any person or entity who is or has been a
      customer of the Company at any time during the period beginning one (1)
      year prior to the date hereof through the Restrictive Period, to purchase
      products or services from any person or entity which products or services
      were previously supplied or performed, as the case may be, by the Company;

                  d.    Solicit, attempt to solicit or aid in the solicitation
      of, any person or entity who is or was a customer, supplier, licensor,
      licensee or person or entity having any other business relationship with
      the Company, at any time during the period beginning one (1) year prior to
      the date hereof through the Restrictive Period, to cease doing business
      with or alter its business relationship with the Company; or

                  e.    Solicit or hire any person or entity who is (i) an
      officer or employee of the Company; or (ii) a director, officer or
      employee of the Company to perform services for any entity other than the
      Company or to terminate his or her employment with any of the foregoing
      entities.

                  f.    The parties believe, in light of the facts known as of
      the date hereof, and after considering the nature and extent of the
      Company's business, the amount of compensation -and other benefits
      provided herein, and the damage that could be done to the Company's
      business by Executive's competing with the Company, that the foregoing
      covenant not to compete is reasonable in time, scope and geographical
      limitation. However, if any court should construe the time, scope or
      geographical limitation of the covenant not to compete to be too broad or
      extensive, it is the intention of the parties that the contract be
      automatically reformed, and as so reformed, enforced, to the maximum
      limits which may be found to be reasonable by such court.

            9.    Binding Effect. This Agreement shall inure to the benefit of
and be binding upon the parties and their respective heirs, successors, legal
representatives and assigns.

            10.   Notices. Any notice required or permitted to be given under
this Agreement shall be sufficient if in writing and either delivered in person
or sent by first class, certified or registered mail, postage prepaid, if to the
Company at the Company's principal place of business, and if to the Executive,
at his home address most recently filed with the Company, or to such other
address as either party shall have designated in writing to the other party.

            11.   Law Governing. This Agreement shall be governed by and
construed in accordance with the laws of the State of Illinois.

            12.   Severability and Construction. If any provisions of this
Agreement is declared void or unenforceable or against public policy, such
provision shall be deemed severable and severed from this Agreement and the
balance of this Agreement shall remain in full force and effect. If a court of
competent jurisdiction determines that any restriction in this Agreement is
overbroad or unreasonable under the circumstances, such restriction shall be
modified or revised by such court to include the maximum reasonable restriction
allowed by law.

            13.   Remedies. Executive and Company acknowledge and agree that
damages would not adequately compensate Company if Executive were to breach any
of his covenants contained in this Agreement. Consequently, Executive agrees
that in the event of any such breach, Company shall be entitled to enforce this
Agreement by means of an injunction or other equitable relief, in addition to
any other remedies available including, without limitation, termination of
Executive's employment for Cause.

            14.   Waiver. Failure to insist upon strict compliance with any of
the terms, covenants or conditions hereof shall not be deemed a waiver of such
term, covenant or condition.

            15.   Entire Agreement Modifications. This Agreement (including all
exhibits hereto) constitutes the entire agreement of the parties with respect to
the subject matter hereof and supersedes all prior agreement, oral and written,
between the parties hereto with respect to the subject matter hereof. This
Agreement may be modified or amended only by an instrument in writing signed by
both parties.

            16.   Employment and Income Taxes. All payments made to Executive
pursuant to this Agreement will be subject to withholding of employment taxes
and other lawful deductions, as applicable.

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                                                                    Exhibit 10.8

            17.   Waiver and Release. Payment by the Company to the Executive of
severance benefits under Section 6 of this Agreement shall be in lieu of any and
all other severance benefits or rights in the case of termination of employment
to which Executive might otherwise be entitled under policies or practices of
the Company or otherwise. In consideration of this Employment Agreement,
Executive, on behalf of himself and his heirs, successors and assigns, forever
releases and discharges the Company, its officers, directors, employees, agents,
affiliates and insurers from any and all known or unknown claims, obligations or
liabilities, whether in contract or tort or based on or through any federal,
state or local statute, including but not limited to the Age Discrimination in
Employment Act, relating to or arising out of Executive's employment with the
Company or the termination of that employment. The foregoing waiver does not
apply to any rights or actions under this Agreement.

            18.   Voluntary Execution of Agreement. Executive represents and
agrees that he has carefully read and fully understands all of the provisions of
this Agreement and that he is voluntarily entering into this Agreement.
Executive further affirms that, prior to the execution of this Agreement, he has
been advised to and has had an opportunity to consult independent counsel
concerning the terms and conditions hereof.

            19.   Indemnification. The Company agrees to indemnify Executive to
the fullest extent permitted under applicable law as provided in the Company's
Bylaws for officers generally.

            20.   Successors and Assigns. This Agreement shall bind and shall
inure to the benefit of the Company and any and all of its successors and
assigns. This Agreement is personal to Executive and shall not be assignable by
Executive. The Company may assign this Agreement to any entity which (i)
purchases all or substantially all of the assets of the Company or (ii) is a
direct or indirect successor (whether by merger, sale of stock or transfer of
assets) of the Company. Any such assignment shall be valid so long as the entity
which succeeds to the Company expressly assumes the Company's obligations
hereunder and complies with its terms.

            21.   Arbitration. Any dispute, controversy or claim between the
Company and the Executive arising out of or relating to this Agreement or the
breach, termination, or invalidity hereof, shall promptly and expeditiously be
submitted to binding arbitration in accordance with the Commercial Arbitration
Rules of the American Arbitration Association in effect at the time of such
arbitration proceeding utilizing a single arbitrator. The arbitration shall
apply the substantive laws of Illinois and beheld in Chicago, Illinois.

            IN WITNESS WHEREOF, the Company and Executive have duly executed and
delivered this Agreement as of the day and year first above written.

                                      A. M. CASTLE CO.
                                      By:
                                             ___________________________________
                                      Title:
                                             ___________________________________

                                      G. THOMAS McKANE

                                      __________________________________________

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