Exhibit 10(iii)A50(a) NATIONAL SERVICE INDUSTRIES, INC. 1992 NONEMPLOYEE DIRECTORS' STOCK OPTION PLAN 1. PURPOSE. (a) The purpose of this Plan is to provide a means by which nonemployee directors of National Service Industries, Inc. (the "Company") may be given an opportunity to purchase stock of the Company. (b) The Company, by means of the Plan, seeks to secure and retain the services of persons best qualified to serve as directors of the Company and to provide incentives for such persons to exert maximum efforts for the success of the Company. (c) This Plan is intended to be an ongoing formula award plan (as described in Rule 16b-3(c)(2)(ii) under the Exchange Act) such that the awards granted hereunder shall not affect the recipients' disinterested status for purposes of administering any stock-related plans of the Company established pursuant to Rule 16b-3 under the Exchange Act. (d) The Company intends that the options issued under the Plan shall be options which do not qualify as incentive stock options for purposes of Section 422 of the Code. 2. DEFINITIONS. For purposes of the Plan: 2.1 "Adjusted Fair Market Value" means, in the event of a Change in Control, the greater of (i) the highest price per Share paid to holders of the Shares in any transaction (or series of transactions) constituting or resulting in a Change in Control or (ii) the highest Fair Market Value of a Share during the ninety (90) day period ending on the date of a Change in Control. 2.2 "Agreement" means the written agreement between the Company and an Optionee evidencing the grant of an Option and setting forth the terms and conditions thereof. 2.3 "Board" means the Board of Directors of the Company. 2.4 "Cause" means the commission of an act of fraud or intentional misrepresentation or an act of embezzlement, misappropriation, or conversion of assets or opportunities of the Company or any subsidiary of the Company. 2.5 "Change in Capitalization" means any increase or reduction in the number of Shares, or any change (including, but not limited to, a change in value) in the Shares or exchange of Shares for a different number or kind of Shares or other securities of the Company, by reason of a reclassification, recapitalization, merger, consolidation, reorganization, spin-off, split-up, issuance of warrants or rights or debentures, stock dividend, stock split or reverse stock split, cash dividend, property dividend, combination or exchange of Shares, repurchase of Shares, change in corporate structure, or otherwise. 2.6 A "Change in Control" means any of the following events: (a) The acquisition (other than from the Company) by any "Person" (as the term is used for purposes of Sections l3(d) or l4(d) of the Exchange Act) of beneficial ownership (within the meaning of Rule l3d-3 promulgated under the Exchange Act) of twenty percent (20%) or more of the combined voting power of the Company's then outstanding voting securities; or (b) The individuals who, as of September 21, 1989 were members of the Board (the "Incumbent Board"), cease for any reason to constitute at least two-thirds of the Board; provided, however, that if the election, or nomination for election by the Company's stockholders, of any new director was approved by a vote of at least two-thirds of the Incumbent Board, such new director shall, for purposes of this Plan, be considered as a member of the Incumbent Board; or (c) Approval by stockholders of the Company of (i) a merger or consolidation involving the Company if the stockholders of the Company immediately before such merger or consolidation do not, as a result of such merger or consolidation, own, directly or indirectly, more than seventy percent (70%) of the combined voting power of the then outstanding voting securities of the corporation resulting from such merger or consolidation in substantially the same proportion as their ownership of the combined voting power of the voting securities of the Company outstanding immediately before such merger or consolidation or (ii) a complete liquidation or dissolution of the Company or an agreement for the sale or other disposition of all or substantially all of the assets of the Company. Notwithstanding the foregoing, a Change in Control shall not be deemed to occur pursuant to Section 2.6(a), solely because twenty percent (20%) or more of the combined voting power of the Company's then outstanding securities is acquired by (i) a trustee or other fiduciary holding securities under one or more employee benefit plans maintained by the Company or any of its subsidiaries or (ii) any corporation which, immediately prior to such acquisition, is owned directly or indirectly by the stockholders of the Company in the same proportion as their ownership of stock in the Company immediately prior to such acquisition. -2- 2.7 "Code" means the Internal Revenue Code of 1986, as amended. 2.8 "Company" means National Service Industries, Inc. 2.9 "Director" means a Director of the Company. 2.10 "Disability" means a physical or mental infirmity which impairs the Optionee's ability to perform substantially his or her duties for a period of one hundred eighty (180) consecutive days. 2.11 "Exchange Act" means the Securities Exchange Act of 1934, as amended. 2.12 "Fair Market Value" on any date means (A) if the Shares are admitted to trading on a national securities exchange, the last sale price reported for the Shares on such exchange on such date or, if no sale was reported on such date, on the last date preceding such date on which a sale was reported, (B) if the Shares are admitted to quotation on the National Association of Securities Dealers Automated Quotation System ("NASDAQ") or other comparable quotation system and have been designated as a National Market System ("NMS") security, the last sale price reported for the Shares on such system on such date or on the last day preceding such date on which a sale was reported, (C) if the Shares are admitted to quotation on NASDAQ and have not been designated a NMS security, the average of the highest bid and lowest asked prices of the Shares on such system on such date, or (D) if there have been no published bid or asked quotations with respect to Shares on such date, the value established by the Board in good faith and in accordance with Section 422 of the Code. 2.13 "Nonemployee Director" means a Director who is not an officer or employee of the Company or any subsidiary. 2.14 "Option" means an option granted under this Plan to purchase Shares. 2.15 "Optionee" means a person to whom an Option has been granted under the Plan. 2.16 "Parent" means any corporation which is a parent corporation (within the meaning of Section 424(e) of the Code) with respect to the Company. 2.17 "Plan" means the National Service Industries, Inc. 1992 Nonemployee Directors' Stock Option Plan. 2.18 "Shares" means the common stock, par value $1.00 per share, of the Company. -3- 3. ADMINISTRATION. 3.1 The Plan shall be administered by the Board. The Board shall have no authority, discretion or power to select the individuals who are or will be eligible to receive Options under this Plan (other than as a consequence of exercising its power to nominate individuals for election to the Board and/or appoint individuals to fill vacancies on the Board). The Board shall not have any discretion to determine the amount, price or timing of any Options granted or to be granted hereunder, except in the sense of administering the Plan pursuant to its express terms. 3.2 The Board shall have the power, subject to, and within the limitations of, the express provisions of the Plan: (a) To construe and interpret the Plan and any Option, to construe and interpret any condition or restrictions imposed on Shares acquired pursuant to the exercise of an Option, to define the terms used herein and to establish, amend, and revoke rule and regulations for administration of the Plan. The Board in the exercise of this power, may correct any defect, omission, or inconsistency in the Plan or in any Agreement, in a manner and to the extent it shall deem necessary or expedient to make the Plan fully effective. (b) To amend, modify, suspend, or terminate the Plan in accordance with Section 9. (c) Generally, to exercise such powers and to perform such acts as the Board deems necessary or expedient to promote the best interests of the Company in connection with the Plan. 4. STOCK SUBJECT TO THE PLAN. 4.1 The maximum number of Shares that may be made the subject of Options granted under the Plan is l00,000 Shares (or the number and kind of Shares of stock or other securities to which such Shares are adjusted upon a Change in Capitalization pursuant to Section 7) and the Company shall reserve for the purposes of the Plan, out of its authorized but unissued Shares or out of Shares held in the Company's treasury, or partly out of each, such number of Shares as shall be determined by the Board. 4.2 Whenever any outstanding Option or portion thereof expires, is forfeited, is cancelled or is otherwise terminated for any reason (other than upon the exercise of the Option or upon the surrender of the Option pursuant to Section 6), the Shares allocable to the cancelled or otherwise terminated Option or portion thereof may again be the subject of Options granted hereunder. -4- 5. OPTION GRANTS FOR NONEMPLOYEE DIRECTORS. 5.1 Grant. An Option shall be granted to each Nonemployee Director on (i) the first business day after the date of the first annual meeting of the stockholders of the Company following adoption of the Plan by the Board, and (ii) the third (3rd) Wednesday occurring in September of each year that the Plan remains in effect pursuant to its terms. The number of Shares and the purchase price therefor of each Option shall be as provided in this Section 5 and such Options shall be evidenced by an Agreement containing such other terms and conditions not inconsistent with the provisions of this Plan as determined by the Board. 5.2 Number of Shares. Each Option granted shall be in respect of a number of Shares equal to 1,000, subject to adjustment as provided in Section 7. 5.3 Purchase Price. The purchase price for Shares under each Option shall be equal to 100% of the Fair Market Value of a Share on the date the Option is granted. 5.4 Duration. Options shall be for a term of ten (10) years, unless terminated earlier as follows: (a) if an Optionee's service as a Director terminates for Cause, the Options granted to the Optionee hereunder shall immediately terminate in full and no rights thereunder may be exercised; (b) if an Optionee's service as a Director terminates for any reason other than Cause, the Optionee (or any guardian, legal representative, heir or successor of the Optionee) may for a period of three (3) years after such termination exercise his or her Options to the extent, and only to the extent, that such Options or portions thereof were vested and exercisable as of the date the Optionee's service as a Director terminated, after which time the Options shall automatically terminate in full. This Section 5.4 shall not be construed to extend the term of any Option or to permit anyone to exercise any Option after expiration of its term, nor shall it be construed to increase the number of Shares as to which any Option is exercisable from the amount exercisable on the date of termination of the Optionee's service as a Director. 5.5 Vesting. Subject to Section 6, each Option shall be exercisable in whole or in part at any time after one (1) year from the date of grant of the Option. 5.6 Non-transferability. No Option granted hereunder shall be transferable by the Optionee to whom granted otherwise than by will or the laws of descent and distribution, and an Option may be exercised during the lifetime of such Optionee only by the Optionee or his or her guardian or legal representative. The terms of such Option -5- shall be final, binding and conclusive upon the beneficiaries, executors, administrators, heirs and successors of the Optionee. 5.7 Method of Exercise. The exercise of an Option shall be made only by a written notice delivered in person or by mail to the Secretary of the Company at the Company's principal executive office, specifying the number of Shares to be purchased and accompanied by payment therefor and otherwise in accordance with the Agreement pursuant to which the Option was granted. The purchase price for any Shares purchased pursuant to the exercise of an Option shall be paid in full upon such exercise in cash, by check or by transferring Shares to the Company upon such terms and conditions as determined by the Board. The written notice pursuant to this Section 5.7 may also provide instructions from the Optionee to the Company that upon receipt of the purchase price in cash from the Optionee's broker or dealer, designated as such on the written notice, in payment for any Shares purchased pursuant to the exercise of an Option, the Company shall issue such Shares directly to the designated broker or dealer. Any Shares transferred to the Company as payment of the purchase price under an Option shall be valued at their Fair Market Value on the day preceding the date of exercise of such Option. If requested by the Board, the Optionee shall deliver the Agreement evidencing the Option to the Secretary of the Company who shall endorse thereon a notation of such exercise and return such Agreement to the Optionee. No fractional Shares (or cash in lieu thereof) shall be issued upon exercise of an Option and the number of Shares that may be purchased upon exercise shall be rounded to the nearest number of whole Shares. 5.8 Rights of Optionees. No Optionee shall be deemed for any purpose to be the owner of any Shares subject to any Option unless and until (i) the Option shall have been exercised pursuant to the terms thereof, (ii) the Company shall have issued and delivered the Shares to the Optionee, and (iii) the Optionee's name shall have been entered as a stockholder of record on the books of the Company. Thereupon, the Optionee shall have full voting, dividend, and other ownership rights with respect to such Shares. 6. EFFECT OF CHANGE IN CONTROL. Notwithstanding anything contained in the Plan or an Agreement to the contrary, in the event of a Change in Control, (i) all Options outstanding on the date of such Change in Control shall become immediately and fully exercisable and (ii) an Optionee will be permitted to surrender for cancellation within sixty (60) days after such Change in Control, any Option or portion of an Option to the extent not yet exercised and the Optionee will be entitled to receive a cash payment in an amount equal to the excess, if any, of (x) the greater of (1) the Fair Market Value, on the date preceding the date of surrender, of the Shares subject to the Option or portion thereof surrendered or (2) the Adjusted Fair Market Value of the Shares subject to the Option or portion thereof surrendered, over (y) the aggregate purchase price for such Shares under the Option or -6- portion thereof surrendered; provided, however, that in the case of an Option granted within six (6) months prior to the Change in Control, the Optionee shall be entitled to surrender for cancellation his or her Option during the sixty (60) day period commencing upon the expiration of six (6) months from the date of grant of any such Option. 7. ADJUSTMENT UPON CHANGES IN CAPITALIZATION. 7.1 Subject to Section 8, in the event of a Change in Capitalization, the Board shall conclusively determine the appropriate adjustments, if any, to the (i) maximum number and class of Shares or other stock or securities with respect to which Options may be granted under the Plan, (ii) the number and class of Shares or other stock or securities which are to be subject to Options to be granted under Section 5; and (iii) the number and class of Shares or other stock or securities which are subject to outstanding Options granted under the Plan, and the purchase price therefor, if applicable; provided, however, that any stock adjustment in the Shares or other stock or securities subject to an outstanding Option (including any adjustments in the purchase price) shall be made only to the extent necessary to maintain the proportionate interest of the Optionee and preserve, without exceeding, the value of such Option. 7.2 If, by reason of a Change in Capitalization, an Optionee shall be entitled to exercise an Option with respect to new, additional or different shares of stock or securities, such new, additional or different shares shall thereupon be subject to all of the conditions which were applicable to the Shares subject to the Option, as the case may be, prior to such Change in Capitalization. 8. EFFECT OF CERTAIN TRANSACTIONS. Subject to Section 6, in the event of (i) the liquidation or dissolution of the Company or (ii) a merger or consolidation of the Company (a "Transaction"), the Plan and the Options issued hereunder shall continue in effect in accordance with their respective terms and each Optionee shall be entitled to receive in respect of each Share subject to any outstanding Option, upon exercise of such Option, the same number and kind of stock, securities, cash, property, or other consideration that each holder of a Share was entitled to receive in the Transaction in respect of a Share. In the event that, after a Transaction, there occurs any change of a type described in Section 2.5 with respect to the shares of the surviving or resulting corporation, then adjustments similar to, and subject to the same conditions as, those in Section 7 shall be made by the Board. 9. TERMINATION AND AMENDMENT OF THE PLAN. The Plan shall terminate on the date that the National Service Industries, Inc. Long-Term Incentive Plan terminates pursuant to its terms (September 19, 1999) and no Option may be granted thereafter. The Board may sooner terminate the Plan and the -7- Board may from time to time amend, modify, or suspend the Plan; provided, however, that: (a) except as provided in Sections 7 and 8, no such amendment, modification, suspension, or termination shall impair or adversely alter any Options or rights theretofore granted under the Plan, except with the consent of the Optionee, nor shall any amendment, modification, suspension, or termination deprive any Optionee of any Shares which he or she may have acquired through or as a result of the Plan; (b) to the extent necessary under Section 16(b) of the Exchange Act and the rules and regulations promulgated thereunder, no amendment shall be effective unless approved by the stockholders of the Company in accordance with applicable law and regulations at an annual or special meeting held within twelve (12) months before or after the date of adoption of such amendment. (c) The provisions of the Plan governing (i) the number of Options to be awarded to Nonemployee Director; (ii) the number of Shares to be covered by each Option; (iii) the exercise price per Share under each Option; (iv) when and under what circumstances each Option will be granted; and (v) the period within which each Option may be exercised shall not be amended more often than once every six (6) months, other than to comport with changes in the Code, the Employee Retirement Income Security Act of 1974, as amended, or the rules and regulations promulgated thereunder. 10. NON-EXCLUSIVITY OF THE PLAN. (a) The adoption of the Plan by the Board shall not be construed as amending, modifying or rescinding any previously approved compensation arrangement or as creating any limitations on the power of the Board to adopt such other compensation arrangements as it may deem desirable, including, without limitation, the granting of stock options otherwise than under the Plan, and such arrangements may be either applicable generally or only in specific cases. -8- (b) Nothing contained in this Plan prohibits a Nonemployee Director from being appointed as an officer or employee of the Company at any time; nor does anything contained in this Plan specifically require a Nonemployee Director to surrender or forfeit an Option solely because he or she accepts an appointment as an officer or employee of the Company at any time after election or appointment to the Board. However, during such time as a Nonemployee Director serves as an officer or employee, he or she shall not be eligible to receive any additional awards under this Plan. 11. LIMITATION OF LIABILITY. As illustrative of the limitations of liability of the Company, but not intended to be exhaustive thereof, nothing in the Plan shall be construed to: (i) give any person any right to be granted an Option other than as specifically provided by the Plan; (ii) give any person any rights whatsoever with respect to Shares except as specifically provided in the Plan; (iii) limit in any way the right of the Company to terminate the service of any person as a Director pursuant to the Company's bylaws and articles of incorporation; or (iv) be evidence of any agreement or understanding, expressed or implied, that the Company will nominate or appoint any person as a Director. 12. REGULATIONS AND OTHER APPROVALS; GOVERNING LAW. 12.1 This Plan and the rights of all persons claiming hereunder shall be construed and determined in accordance with the laws of the State of Delaware without giving effect to the conflicts of laws principles thereof, except to the extent that such law is preempted by federal law. 12.2 The obligation of the Company to sell or deliver Shares with respect to Options granted under the Plan shall be subject to all applicable laws, rules and regulations, including all applicable federal and state securities laws, and the obtaining of all such approvals by governmental agencies as may be deemed necessary or appropriate by the Board. 12.3 The Plan is intended to comply with Rule 16b-3 promulgated under the Exchange Act and the Board shall interpret and administer the provisions of the Plan or any Agreement in a manner consistent therewith. Any provisions inconsistent with such Rule shall be inoperative and shall not affect the validity of the Plan. -9- 12.4 Each Option is subject to the requirement that, if at any time the Board determines, in its discretion, that the listing, registration, or qualification of Shares issuable pursuant to the Plan is required by any securities exchange or under any state or federal law, or the consent or approval of any governmental regulatory body is necessary or desirable as a condition of, or in connection with, the grant of an Option or the issuance of Shares, no Options shall be granted or payment made or Shares issued, in whole or in part, unless listing, registration, qualification, consent, or approval has been effected or obtained free of any conditions as acceptable to the Board. 12.5 Notwithstanding anything contained in the Plan to the contrary, in the event that the disposition of Shares acquired pursuant to the Plan is not covered by a then current registration statement under the Securities Act of 1933, as amended, and is not otherwise exempt from such registration, such Shares shall be restricted against transfer to the extent required by the Securities Act of 1933, as amended, and Rule 144 or other regulations thereunder. The Board may require any individual receiving Shares pursuant to the Plan, as a condition precedent to receipt of such Shares upon exercise of an Option, to represent and warrant to the Company in writing that the Shares acquired by such individual are acquired without a view to any distribution thereof and will not be sold or transferred other than pursuant to an effective registration thereof under said Act or pursuant to an exemption applicable under the Securities Act of 1933, as amended, or the rules and regulations promulgated thereunder. The certificates evidencing any of such Shares shall be appropriately inscribed with a legend reflecting their status as restricted securities as aforesaid. 13. DESIGNATION OF BENEFICIARY. Each Optionee may designate a person or persons to receive in the event of his or her death, any Option or any amount payable pursuant thereto, to which he or she would then be entitled. Such designation will be made upon forms supplied by and delivered to the Company and may be revoked in writing. If an Optionee fails effectively to designate a beneficiary, then his or her estate will be deemed to be the beneficiary. 14. EFFECTIVE DATE. The effective date of the Plan shall be the date of its adoption by the Board, subject only to the approval by the affirmative votes of the holders of a majority of the securities of the Company present, or represented, and entitled to vote at a meeting of stockholders duly held in accordance with the applicable laws of the State of Delaware within twelve (12) months of such adoption. -10-