UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                    FORM 10-Q

(Mark One)

[ X ]    QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                For the quarterly period ended September 30, 1998

                                       OR

[    ]   TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                         Commission file number 0-16225

                                      EMCON

             (Exact name of Registrant as specified in its charter)


             California                                        94-1738964
 ----------------------------------                       ---------------------
(State or other jurisdiction of                            (I.R.S. Employer
incorporation or organization)                              Identification No.)

400 South El Camino Real, Suite 1200
San Mateo, California                                             94402
----------------------------------------------                 ------------
(Address of  principal executive offices)                       (Zip Code)


       Registrant's telephone number, including area code: (650) 375-1522

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the  preceding 12 months (or for such  shorter  period that the  registrant  was
required  to file  such  reports),  and  (2) has  been  subject  to such  filing
requirements for the past 90 days. Yes [ X ] No [ ]

8,723,099 shares of Common Stock Issued and Outstanding as of November 3, 1998.

                                       1
<PAGE>


                                      EMCON
                               REPORT ON FORM 10-Q
                    FOR THE QUARTER ENDED SEPTEMBER 30, 1998



                                                                           Page
                                                                          Number
                                                                          ------

FACING SHEET .............................................................   1

INDEX ....................................................................   2

PART I.   FINANCIAL INFORMATION

         Item 1.      Financial Statements

                      Consolidated Balance Sheets -
                      September 30, 1998 and December 31, 1997............   3

                      Consolidated Statements of Income -
                      Three and nine months ended September 30, 
                      1998 and 1997.......................................   4

                      Consolidated Statements of Cash Flows -
                      Nine months ended September 30, 1998 and 1997......    5

                      Notes to Consolidated Financial Statements.........    6

        Item 2.       Management's Discussion and Analysis of
                          Financial Condition and Results of          
                          Operations.....................................   12

   PART II. OTHER INFORMATION............................................   16

Signatures...............................................................   17

Index to                                                             
  Exhibits................................................................. 18


                                       2
<PAGE>
<TABLE>
<CAPTION>


   EMCON
   CONSOLIDATED BALANCE SHEETS
 --------------------------------------------------------------------------------- ------------------ ----------------
                                                                                     September 30,     December 31,
                                                                                         1998              1997
 (In thousands, except share amounts)                                                 (Unaudited)        (Audited)
 --------------------------------------------------------------------------------- ------------------ ----------------
<S>                                                                                   <C>               <C>
 
 ASSETS
 Current Assets:
 Cash and cash equivalents                                                            $  4,260         $  6,106
 Accounts Receivable:
     Billed accounts receivable, net of allowance for doubtful accounts
       of $748 and $634 at September 30, 1998 and December 31, 1997, respectively       35,739           31,413
     Unbilled accounts receivable, net of allowance for doubtful accounts
       of $460 and $295 at September 30, 1998 and December 31, 1997, respectively        7,218            5,310
 Costs and estimated earnings in excess of billings on
     uncompleted contracts                                                               1,598              678
 Prepaid expenses and other current assets                                               3,352            3,401
 Inventory                                                                               3,017            2,238
 Deferred taxes, current portion                                                         3,235            4,235
                                                                                      --------         --------
     Total Current Assets                                                               58,419           53,381
 Net property and equipment, at cost                                                    16,180           16,182
 Notes receivable                                                                        2,326            2,811
 Cash surrender value of insurance policies                                              3,113            2,346
 Other assets                                                                            2,599            2,597
 Deferred tax assets                                                                     1,028            1,028
 Goodwill, net of amortization                                                          14,747           13,916
 Other intangible assets, net of amortization                                              868              814
                                                                                     ---------        ---------
     Total Assets                                                                      $99,280          $93,075
                                                                                       =======          =======
 LIABILITIES AND SHAREHOLDERS' EQUITY
 Current Liabilities:
 Accounts payable                                                                      $11,507         $  8,391
 Accrued payroll and related benefits                                                    5,958            4,356
 Other accrued liabilities                                                               4,723            2,969
 Billings in excess of costs and estimated earnings
     on uncompleted contracts                                                            2,876            2,732
 Long-term obligations due within one year                                               2,263            2,350
                                                                                      --------         --------
     Total Current Liabilities                                                          27,327           20,798
 Long-term debt                                                                          9,786           11,441
  Other noncurrent obligations                                                           2,083            2,736
 Commitments and contingencies                                                              --               --
 Shareholders' Equity:
 Preferred stock, no par value, 5,000,000 shares authorized;
     no shares issued or outstanding                                                        --               --
 Common stock, no par value, 15,000,000 shares authorized;
     8,723,099 and 8,571,764 shares issued and outstanding at
     September 30, 1998 and December 31, 1997, respectively                             42,875           42,184
 Retained earnings                                                                      17,209           15,916
                                                                                       -------          -------
     Total Shareholders' Equity                                                         60,084           58,100
                                                                                       -------          -------
     Total Liabilities and Shareholders' Equity                                        $99,280          $93,075
                                                                                       =======          =======
See accompanying notes.

</TABLE>
                                       3
<PAGE>

<TABLE>
<CAPTION>

EMCON
CONSOLIDATED STATEMENTS OF INCOME
---------------------------------------------------------------------------------------------------------------------------
                                                                    Three months ended              Nine months ended
                                                                      September 30,                   September 30,
                                                                       (Unaudited)                     (Unaudited)
                                                                ---------------------------    ----------------------------
(In thousands, except per share amounts)                              1998          1997             1998           1997
---------------------------------------------------------------------------------------------------------------------------
<S>                                                                  <C>           <C>             <C>            <C>

Gross revenue                                                        $41,585       $40,764         $111,349       $105,241
Outside services at cost                                               5,954        10,865           13,687         23,294
                                                                     -------       -------         --------       --------

         Net revenue                                                  35,631        29,899           97,662         81,947

Costs and expenses:
     Direct expenses                                                  21,809        15,916           57,610         40,728
     Indirect expenses                                                12,254        12,194           37,151         37,597
     Restructuring/other charges                                          --            --               --            (75)
     Loss on disposition of laboratory                                    --            --               --            333
     Gain on sale of assets                                               --            --               --           (826)
                                                                      ------        ------           ------         ------

         Income from operations                                        1,568         1,789            2,901          4,190

Interest income                                                         (125)         (145)            (444)          (364)
Interest expense                                                         294           275              891            923
Equity in earnings of affiliates                                          --           (63)             (15)           (97)
Minority interest (income) expense                                        11           271               (9)           454
                                                                      ------        ------           ------         ------

Income before provision for income taxes                               1,388         1,451            2,478          3,274
Provision for income taxes                                               658           508            1,154          1,146
                                                                      ------        ------           ------         ------

Net income                                                            $  730        $  943           $1,324         $2,128
                                                                      ======        ======           ======         ======

Basic earnings per share                                              $ 0.08        $ 0.11           $ 0.15         $ 0.25
                                                                      ======        ======           ======         ======

Diluted earnings per share                                            $ 0.08        $ 0.11           $ 0.15         $ 0.25
                                                                      ======        ======           ======         ======

Shares used in computing basic earnings per share                      8,723         8,557            8,670          8,541
                                                                      ======        ======           ======         ======

Shares used in computing diluted earnings per share                    8,816         8,768            8,856          8,608
                                                                      ======        ======           ======         ======

See accompanying notes.

</TABLE>
                                       4
<PAGE>
<TABLE>
<CAPTION>


EMCON
CONSOLIDATED STATEMENTS OF CASH FLOWS

----------------------------------------------------------------------------------------------------------
                                                                                 Nine months ended
                                                                                   September 30,
                                                                                    (Unaudited)
                                                                           -------------------------------
Increase (decrease) in cash and cash equivalents (in thousands)                  1998             1997
----------------------------------------------------------------------------------------------------------
<S>                                                                             <C>              <C>    

Cash flow from operating activities:
Net income                                                                      $1,324           $2,128
Adjustments to reconcile net income to net cash provided by (used for)
operating activities:
   Depreciation                                                                  2,818            2,776
   Amortization                                                                    491              477
   Bad debt expense                                                                691            1,022
   Gain (loss) on sale/disposal of property and equipment                         (230)              48
   Loss on disposition of laboratory                                                --              333
   Gain on disposition of assets                                                    --             (826)
   Increase in salary continuation plan                                            187               64
   Changes in operating assets and liabilities:
       Accounts receivable                                                      (6,567)          (8,396)
       Costs and estimated earnings in excess of billings on uncompleted          (920)          (1,344)
       contracts
       Inventory                                                                  (779)            (908)
       Prepaid expenses and other assets                                            --              217
       Notes receivable                                                            485           (2,375)
       Cash surrender value of insurance policies                                 (767)            (409)
       Other assets                                                                  3            2,290
       Deferred tax assets                                                       1,000               --
       Accounts payable                                                          2,893            3,857
       Accrued payroll and related benefits                                      1,587             (111)
       Billings in excess of costs and estimated earnings on uncompleted           144            1,209
       projects
       Other accrued liabilities                                                   868            2,851
----------------------------------------------------------------------------------------------------------

          Net cash provided by operating activities                              3,228            2,903
----------------------------------------------------------------------------------------------------------
Cash flow from investing activities:
   Additions to property and equipment                                          (2,968)          (3,222)
   Acquisitions, net of cash acquired                                             (719)            (858)
   Addition to other intangible assets                                            (101)              --
   Net cash on disposition of laboratory                                            --            3,794
   Net cash from dispositions of assets                                             --              840
   Proceeds from sale of property and equipment                                    389              122
----------------------------------------------------------------------------------------------------------

          Net cash (used for) provided by investing activities                  (3,399)             676
----------------------------------------------------------------------------------------------------------
Cash flow from financing activities:
   Proceeds of new debt obligation                                                  58              137
   Payments of current and long term portion of debt                            (1,800)          (5,165)
   Issuance of common stock for cash, net of cancellations                          98              210
   Dividend payments                                                               (31)             (30)
----------------------------------------------------------------------------------------------------------

          Net cash used for financing activities                                (1,675)          (4,848)
----------------------------------------------------------------------------------------------------------
Decrease in cash and cash equivalents                                           (1,846)          (1,269)
Cash and cash equivalents, beginning of year                                     6,106            5,331
----------------------------------------------------------------------------------------------------------
Cash and cash equivalents, end of period                                        $4,260           $4,062
----------------------------------------------------------------------------------------------------------
See accompanying notes.

</TABLE>
                                       5
<PAGE>


                                      EMCON

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                   (Unaudited)

1.   Basis of Presentation

     The accompanying  consolidated financial statements include the accounts of
     the Company and its  wholly-owned  subsidiaries  after  elimination  of all
     significant intercompany accounts and transactions.

     While the financial information is unaudited, the statements in this report
     reflect all adjustments, which are normal and recurring, that are necessary
     for a fair  presentation  of the  results  of  operations  for the  interim
     periods covered and of the financial  condition of the Company at the dates
     of the consolidated balance sheets. The consolidated  operating results for
     the interim periods presented are not necessarily indicative of performance
     for the entire year.

     These  consolidated  financial  statements  and  notes  should  be  read in
     conjunction with the Company's  consolidated  financial  statements for the
     fiscal year ended December 31, 1997.

2.   Restructuring Charges

     In the fourth  quarter of 1996,  senior  management  reviewed the Company's
     operational  and  administrative  functions  for  the  purpose  of  further
     improving the Company's competitiveness and overall profitability. Based on
     this  review,  the  Company's  Board  of  Directors  approved  a  strategic
     restructuring  plan to  reposition  the  Company to fully  exploit its core
     strengths in engineering, design, construction, operations and maintenance.
     The  plan  included  closure  or  downsizing  of  underperforming  offices,
     write-off  of  employment   contracts   for  former   employees  no  longer
     participating in the Company's affairs and employee  severance.  During the
     quarter  ended  September  30,  1998,  $6,000  of  costs  relating  to  the
     restructuring  were incurred and charged  against an  established  reserve.
     Through  September  30,  1998,  $405,000 of  restructuring  costs have been
     incurred  and  charged  against  the  reserve  and  $286,000 of the reserve
     remains  in  other  accrued  liabilities,   which  includes  present  value
     adjustments during 1998 of $18,000.

3.   Acquisitions

     On April 3, 1998,  EMCON  acquired  all the  outstanding  capital  stock of
     Advanced  Analytical  Solutions,  Inc.  ("A2S"),  a provider of alternative
     dispute resolution,  cost allocation, cost recovery, and litigation support
     services  primarily  for  superfund  projects.  A2S has  offices in Denver,
     Colorado and  Philadelphia,  Pennsylvania.  The Company  purchased  A2S for
     $593,000 in stock and $601,000 in cash and direct  acquisition  costs.  The
     transaction  was  accounted  for as a purchase.  Goodwill of  approximately
     $1,150,000  is being  amortized  over twenty years using the straight  line
     method.  Accumulated  amortization at September 30, 1998, was approximately
     $29,000.  Additional  consideration  may be paid  for the  purchase  of A2S
     subject to the achievement of  predetermined  operating  performance  goals
     over the next two  years.  This  acquisition  would not have had a material
     affect on net  revenue,  net  income,  or earnings  per share,  had it been
     effective at January 1, 1998.

                                       6

<PAGE>


     Effective May 1, 1997,  Organic Waste Technology,  Inc.  ("OWT"),  a wholly
     owned subsidiary of EMCON,  acquired all of the equity interest in National
     Earth Products, Inc. ("NEP"), a Lancaster,  Pennsylvania-based company with
     significant  expertise in landfill  civil  construction  and related  soils
     processing.  NEP was  acquired  for  $933,000 in cash and $800,000 in notes
     payable.  The  transaction  was accounted  for as a purchase.  Specifically
     identifiable  intangible  assets and goodwill of  approximately  $1,601,000
     resulting  from this  acquisition  are  included in goodwill  and are being
     amortized   over   twenty-five   years  using  the  straight  line  method.
     Accumulated  amortization  as of  September  30,  1998,  was  approximately
     $86,000.  Included in goodwill, is an additional $125,000 cash payment that
     was made to NEP  shareholders  in May, 1998, as a result of their attaining
     certain predetermined operating performance goals. Additional consideration
     may be paid for the purchase of NEP subject to the  achievement  of certain
     earnout  goals over the next year to be  measured as of April,  1999.  This
     acquisition  would  not have had a  material  effect  on net  revenue,  net
     income, or earnings per share, had it been effective at January 1, 1997.

4.   Credit Agreement

     In  conjunction  with the  acquisition of OWT in the first quarter of 1996,
     the Company  entered into a $20,000,000  secured credit  agreement with its
     existing commercial bank (the "Credit  Agreement"),  replacing its previous
     $10,000,000 unsecured line of credit. Under the new agreement,  the Company
     borrowed  $10,000,000  on a term loan basis with interest at a managed rate
     not to exceed the prime rate. Principal is to be amortized over seven years
     with any unpaid  amounts due and payable on June 30,  2001.  In April 1997,
     following  the  infusion  of cash  upon  the  sale of  Columbia  Analytical
     Services, Inc., the Company prepaid, on an accelerated basis, $3,000,000 of
     the then  outstanding  principal  balance of the term loan.  The  remaining
     $10,000,000  under the Credit  Agreement is available  for working  capital
     purposes in the form of a line of credit (with up to $5,000,000  also being
     available for non-working  capital purposes).  The line of credit component
     of the Credit  Agreement  expires on November 30, 1998. The Company expects
     to renew the line of credit  component of the Credit Agreement prior to its
     expiration.  The Credit Agreement  contains  provisions with respect to the
     payment of dividends and the level of capital expenditures and requires the
     maintenance of specific levels of working  capital,  tangible net worth and
     continued quarterly profitability.

5.   Litigation

    As a professional  services firm engaged in  environmental-related  matters,
    the Company encounters potential liability, including claims for significant
    environmental damage, in the normal course of business. The Company is party
    to lawsuits and is aware of potential  exposure  related to certain  claims,
    but in the opinion of  management  the  resolution of these matters will not
    have a  material  adverse  effect on the  Company's  consolidated  financial
    position, results of operations or cash flows.


                                       7
<PAGE>


6.  Earnings Per Share

<TABLE>

<CAPTION>
                                                                 Three months ended               Nine months ended
                                                                    September 30                     September 30
                                                           ------------------------------   ----------------------------
    (In thousands, except for earnings per share)                 1998             1997            1998            1997
    --------------------------------------------------------------------------------------------------------------------
    <S>                                                            <C>              <C>           <C>              <C>
     
     Numerator:
     Net income                                                    $  730          $  943         $1,324           $2,128
                                                                   ------          ------         ------           ------
     Numerator for basic earnings per share -
         income available to common stockholders                      730             943          1,324            2,128
     Effect of dilutive securities:
         8% convertible debentures                                    N/A(1)          N/A(1)         N/A(1)           N/A(1)
                                                                   ------          ------         ------            -----
     Numerator for diluted earnings per share -
         income available to common stockholders
         after assumed conversions                                 $ 730           $  943         $1,324           $2,128
                                                                   =====           ======         ======           ======
    Denominator:
    Denominator for basic earnings per share -
         weighted-average shares                                   8,723            8,557          8,670            8,541
    Effect of dilutive securities:
         Employee stock options                                       93              211            186               67
         8% convertible debentures                                   N/A(1)           N/A(1)         N/A(1)           N/A(1)
    Dilutive potential common shares
    Denominator for diluted earnings per share -
         adjusted weighted average shares and assumed
         conversions                                               8,816            8,768          8,856            8,608
                                                                  ======           ======         ======           ======
    Basic earnings per share                                      $ 0.08           $ 0.11         $ 0.15           $ 0.25
                                                                  ======           ======         ======           ======
    Diluted earnings per share                                    $ 0.08           $ 0.11         $ 0.15           $ 0.25
                                                                  ======           ======         ======           ======
    ------------------------------------------------------ --------------- ---------------- -------------- ---------------
  (1)Excluded from the above  reconciliations were approximately  269,000 shares
  of common stock that may be issued at $6.50 per share to convert $1,747,000 of
  indebtedness  to certain  senior  management  of OWT because  such shares were
  antidilutive at September 30, 1998. Conversion of debt, if it occurs, would be
  within  ninety days after  November 30,  2001.  Also  excluded  from the above
  reconciliations were approximately  123,000 shares of common stock that may be
  issued at $6.50 per share to  convert  $800,000  of  indebtedness  to  certain
  senior  management of NEP because such shares were  antidilutive  at September
  30, 1998.  Conversion of debt, if it occurs,  would be 50% at May 1, 2000, and
  50% at May 1, 2002.
</TABLE>

7.   Other

    In 1994, the Company converted to a  fifty-two/fifty-three  week fiscal year
    which will result in a fifty-two  week year in 1998.  The Company's year end
    falls  on the  Friday  closest  to the last day of the  calendar  year.  The
    Company also follows a five-four-four week quarterly cycle. For convenience,
    the accompanying consolidated financial statements have been shown as ending
    on the last day of the calendar period.

8.   Adoption of Statement 131

     Effective  January 1, 1998,  the Company  adopted the Financial  Accounting
     Standards  Board's  Statement of Financial  Accounting  standards  No. 131,
     Disclosure  about  Segments  of  an  Enterprise  and  Related  Information,
     ("Statement  131").  Statement 131 superseded FASB Statement 14,  Financial
     Reporting for Segments of a Business Enterprise.  Statement 131 establishes
     standards for the way that public business  enterprises  report information
     about operating  segments in annual financial  statements and requires that
     those enterprises  report selected  information about operating segments in
     interim  financial  reports.  The adoption of Statement  131 did not affect
     consolidated  results of operations or financial  position,  but did affect
     the disclosure of segment information. See note 9.


                                       8
<PAGE>


9.   Segment Reporting

     Description  of the types of services  from which each  reportable  segment
     derives its revenues.

     The  Company  provides  comprehensive  environmental  engineering,  design,
     construction,   operations  and  maintenance,   and  equipment  fabrication
     services  to a variety of public and  private  industrial  and solid  waste
     clients.  The  Company  is  comprised  of two  reportable  segments  -- the
     Operations and Construction  Division (EOC) and the  Professional  Services
     Division (PSD) -- and services three key service lines:  Solid Waste,  Site
     Restoration and Facility Services.

     In the first  quarter of 1997,  the  Company  had,  in  addition to the two
     reportable  segments listed above, a third reportable segment which was its
     laboratory  operations known as Columbia Analytical  Services,  Inc. (CAS).
     During the first quarter of 1997, the Company completed the sale of CAS.

     Measurement of segment profit or loss and segment assets.

     The Company evaluates performance of its reportable segments,  EOC and PSD,
     based on  operating  income or loss  before  and after  corporate  overhead
     allocations, but before interest income, interest expense, equity in income
     of affiliates  and minority  interest  income  (loss).  Corporate  overhead
     expenses are  substantially  allocated to the reporting  segments  based on
     revenue and/or headcount when an item is not  specifically  identified to a
     reporting segment.  The accounting  policies of the reportable segments are
     the  same as those  described  in the  summary  of  significant  accounting
     policies as disclosed in EMCON's Form 10K as of December 31, 1997.

     Intersegment  sales consist primarily of labor and are marked up to provide
     the  supplying  reportable  segment  a measure  of  profit.  The  receiving
     reportable  segment records the transfer as an "Outside Service" and may or
     may not further mark up the labor cost prior to passing the cost through to
     its  customer.  If the cost is not  passed  through  to the  customer,  the
     receiving  reportable  segment records the transaction as an indirect cost.
     All intersegment accounts are eliminated in consolidation.

     Factors management used to identify the enterprise's reportable segments.

     The Company's reportable segments are divisional units that offer different
     services.  The  reportable  segments are each managed  separately.  The PSD
     reportable  segment  concentrates on professional  engineering,  design and
     consulting  services  in  solid  waste,  site  restoration  and  facilities
     services.  The PSD reportable segment has regional  operations  situated in
     the North,  South,  Northwest and Southwest  portions of the United States,
     each overseen by an Area Operations Manager. These regional operations have
     the same  operating  parameters  (services  offered and required  operating
     margins),  may serve the same national customers and often share personnel.
     For reportable segment reporting, these regional operations are aggregated.
     The  EOC  reportable  segment   concentrates  on  construction,   drilling,
     equipment fabrication and operations and maintenance services, primarily to
     the Company's solid waste clients.

     In  1997,  there  was  a  third  reportable  segment,  Columbia  Analytical
     Services,  Inc.,  a  laboratory  division  that was sold  during  the first
     quarter of 1997.

                                       9
<PAGE>

<TABLE>
<CAPTION>


     Segment Information
       ---------------------------------------------------------------------------------------------------
       (Three months ended September 30, 1998)                  PSD        EOC        Other         Total
       ---------------------------------------------------------------------------------------------------
       <S>                                                  <C>        <C>            <C>         <C>

       Gross revenues from:
            External subcontractors                         $23,134    $17,920       $  531       $41,585
            Intersegment revenues                             1,137      1,405           --         2,542
       Outside services from:
            External subcontractors                           5,921          2           31         5,954
            Intersegment services                             1,505      1,039            3         2,547
       Net revenues                                          16,845     18,284          502        35,631
       Depreciation expense                                     500        354           69           923
       Amortization expense                                      --         16          159           175
       Segment operating profit (loss) before                 2,713      1,191          133         4,037
       allocations
       Segment operating profit (loss) after allocations      1,602        642         (676)        1,568
       ---------------------------------------------------------------------------------------------------
       (Three months ended September 30, 1997)
       ---------------------------------------------------------------------------------------------------
       Gross revenues from:
            External customers                              $22,037    $18,725        $   2       $40,764
            Intersegment revenues                               443        593           --         1,036
       Outside services from:
            External subcontractors                           5,139      5,726           --        10,865
            Intersegment services                               645        376           --         1,021
       Net revenues                                          16,696     13,216          (13)       29,899
       Depreciation expense                                     581        200           87           868
       Amortization expense                                      --         29          136           165
       Segment operating profit (loss) before                 2,047      1,404           --         3,451
       allocations
       Segment operating profit (loss) after allocations        918        844           27         1,789
       ---------------------------------------------------------------------------------------------------


       ----------------------------------------------------------------------------------------------------------------
       (Nine months ended September 30, 1998)                   PSD        EOC          CAS        Other         Total
       ----------------------------------------------------------------------------------------------------------------
       Gross revenues from:
            External customers                              $61,465    $48,895          N/A        $ 989      $111,349
            Intersegment revenues                             2,009      2,558          N/A           --         4,567
       Outside services from:
            External subcontractors                          13,535        105          N/A           47        13,687
            Intersegment services                             2,753      1,833          N/A            8         4,594
       Net revenues                                          47,186     49,515          N/A          961        97,662
       Depreciation expense                                   1,581      1,032          N/A          205         2,818
       Amortization expense                                      --         46          N/A          445           491
       Segment operating profit (loss) before                 3,908      4,465          N/A          259         8,632
       allocations
       Segment operating profit (loss) after allocations        807      2,873          N/A         (779)        2,901
       Segment assets (1)
           Accounts receivable, net                          23,829     18,688          N/A          440        42,957
       ----------------------------------------------------------------------------------------------------------------
        (1)  The Company reviews its consolidated balance sheet and reviews only
          accounts receivable on a segment basis.

</TABLE>
                                       10
<PAGE>

<TABLE>
<CAPTION>

       -----------------------------------------------------------------------------------------------------------------
       (Nine months ended September 30, 1997)                   PSD        EOC           CAS         Other        Total
       -----------------------------------------------------------------------------------------------------------------
       <S>                                                  <C>        <C>            <C>           <C>        <C>

       Gross revenues from:
            External customers                              $63,143    $37,633        $4,453        $  12      $105,241
            Intersegment revenues                             1,136      1,684           734           --         3,554
       Outside services from:
            External subcontractors                          12,780     10,239           275           --        23,294
            Intersegment services                             2,708        776             8           --         3,492
       Net revenues                                          48,791     28,302         4,904          (50)       81,947
       Depreciation expense                                   1,700        846           462          230         3,238
       Amortization expense                                      --         70            --          407           477
       Restructuring/other charges                               --         --            --          (75)          (75)
       Loss on disposition of laboratory                         --         --            --          333           333
       Gain on sale of assets                                    --        826            --           --           826
       Segment operating profit (loss) before                 5,076      3,682           108           --         8,866
       allocations
       Segment operating profit (loss) after allocations      2,184      2,176           (59)        (111)        4,190
       Segment assets(1)
            Accounts receivable, net                         27,491     14,059           N/A           --        41,550
       -----------------------------------------------------------------------------------------------------------------
     (1)The  Company  reviews its  consolidated  balance  sheet and reviews only
     accounts receivable on a segment basis.

</TABLE>
                            

<TABLE>
<CAPTION>
       ------------------------------------------------------------------------------------------------------------------

                                                                         Three months ended          Nine months ended
                                                                            September 30,              September 30,
       ------------------------------------------------------------------------------------------------------------------
       Three months ended September 30,                                      1998        1997           1998        1997
       ------------------------------------------------------------------------------------------------------------------
       <S>                                                                <C>         <C>           <C>         <C>

       Revenues
       Total external revenues for reportable segments                    $41,054     $40,762       $110,360    $105,229
       Intersegment revenues for reportable segments                        2,542       1,036          4,567       3,554
       Other revenues                                                         531           2            989          12
       Elimination of intersegment revenues                                (2,542)     (1,036)        (4,567)     (3,554)
                                                                          -------     -------       --------    --------
            Total gross consolidated revenues                              41,585      40,764        111,349     105,241
       Less outside services                                               (5,954)    (10,865)       (13,687)    (23,294)
                                                                          -------     -------       --------    --------
             Total net revenue                                            $35,631     $29,899        $97,662     $81,947
       ------------------------------------------------------------------------------------------------------------------
       Profit or Loss
       Total operating profit for reportable segments before              $ 4,037     $ 3,451        $ 8,632     $ 8,866
       allocations
       Overhead allocations expense                                        (1,660)     (1,689)        (4,693)     (4,565)
       Unallocated overhead                                                  (809)         27         (1,038)       (111)
                                                                          -------      ------        -------     -------
             Total operating profit after allocations                       1,568       1,789          2,901       4,190
       Interest income                                                        125         145            444         364
       Interest expense                                                      (294)       (275)          (891)       (923)
       Equity in earnings of affiliates                                        --          63             15          97
       Minority interest income (expense)                                     (11)       (271)             9        (454)
                                                                          -------      ------        -------     -------
                                                                                            
            Income before provision for income taxes                       $1,388      $1,451        $ 2,478     $ 3,274
       ------------------------------------------------------------------------------------------------------------------
       September 30,                                                                            1998                1997
       ------------------------------------------------------------------------------------------------------------------
       Assets
       Accounts receivable for reportable segments                                           $42,957             $41,550
       Other current assets                                                                   15,462              11,904
       Net property and equipment at cost                                                     16,180              15,371
       Goodwill, net of amortization                                                          14,747              13,786
       Other assets                                                                            9,934              13,798
                                                                                             -------             -------
            Total consolidated assets                                                        $99,280             $96,409
       ------------------------------------------------------------------------------------------------------------------
      
</TABLE>
                                       11

<PAGE>



                                      EMCON

ITEM 2.       Management's  Discussion  and  Analysis of Financial Condition and
              Results Of Operations.

              The following  discussion  should be read in conjunction  with the
              consolidated  financial  statements  and notes  thereto  appearing
              elsewhere  in  this  Form  10-Q.   Certain   statements   in  this
              "Management's  Discussion and Analysis of Financial  Condition and
              Results  of  Operations,"   including   statements  regarding  the
              Company's  beliefs,   expectations  or  strategies  regarding  the
              future, constitute  forward-looking  statements within the meaning
              of Section  27A of the  Securities  Act of 1933 and Section 21E of
              the Securities Exchange Act of 1934. Although the Company believes
              that the expectations reflected in such forward-looking statements
              are based on reasonable  assumptions,  such statements are subject
              to risks and  uncertainties,  including  those discussed under the
              heading "Risk Factors" in the Company's Annual Report on Form 10-K
              for the year ended December 31, 1997 (the "1997 Form 10-K"),  that
              could  cause  actual  results  to  differ  materially  from  those
              projected.

RESULTS OF OPERATIONS

Current  Year-to-Date ended  September 30, 1998  versus Prior Year-to-Date ended
September 30, 1997.

Net Revenue:  Net revenue for the first nine months of 1998 totaled $97,662,000,
a 19.2% increase from  $81,947,000 for the first nine months of 1997. At the end
of the first quarter of 1997, the Company  divested its  laboratory  subsidiary,
Columbia Analytical Services,  Inc. (CAS); a reportable segment. CAS contributed
$4,904,000  to net revenue in the first  quarter of 1997.  Excluding net revenue
contributed  by CAS in the first  quarter of 1997,  net revenue from  continuing
operations  increased 26.8% in the first nine months of 1998 from $77,043,000 in
the same period in 1997.  The  increase in net  revenue was  primarily  due to a
75.0%  increase in net revenue from EMCON's  Operations and  Construction  (EOC)
reportable  segment as the demand for its services  continued to increase.  This
was offset by a 3.3%  decrease in net  revenue  from the  Professional  Services
Division (PSD) reportable segment due to unanticipated project delays, unusually
severe  weather  conditions  and the  contraction  of the  PSD's  Northwest  and
Southwest operations  throughout the course of 1997 and the first nine months of
1998.

Direct  Expenses:  Direct expenses  include  compensation for billable hours for
technical and professional staff and other project related expenses,  as well as
direct labor and  materials  for  in-house  testing,  construction  and drilling
activities.   Direct  expenses  for  the  first  nine  months  of  1998  totaled
$57,610,000,  a 41.5% increase compared to direct expenses of $40,728,000 during
the first nine  months of 1997.  Excluding  the  impact of CAS  (which  incurred
direct  expenses of  $2,267,000  in the first  quarter of 1997) direct  expenses
increased  49.8%  from  $38,461,000  in the  first  nine  months  of 1997.  As a
percentage of net revenue,  direct expenses as reported  increased from 49.7% in
the first  nine  months of 1997 to 59.0% in the first nine  months of 1998.  The
increase  was due in large part to a shift in business  mix  resulting  from the
divestiture  of CAS,  the  contraction  of the PSD  reportable  segment  and the
continued expansion of the EOC reportable segment.


                                       12
<PAGE>


Indirect Expenses: Indirect expenses include salary compensation for nonbillable
hours  of  professional,   technical  and   administrative   staff  and  general
administrative  expenses  such as rent,  bonuses,  benefits,  insurance,  legal,
depreciation and  amortization.  Indirect  expenses for the first nine months of
1998  totaled  $37,151,000,  a 1.2%  decrease  compared to indirect  expenses of
$37,597,000  for the first  nine  months of 1997.  Excluding  the  impact of CAS
(which  incurred  indirect  expenses of $2,529,000 in the first quarter of 1997)
indirect  expenses  during the first  nine  months of 1998  increased  5.9% from
$35,068,000  during  the first  nine  months  of 1997.  As a  percentage  of net
revenue,  indirect  expenses as reported  decreased from 45.9% in the first nine
months of 1997 (42.8% after  excluding  the impact of CAS) to 38.0% in the first
nine months of 1998.  The decrease was due in part to the  above-noted  shift in
business mix, the expansion of the EOC reportable  segment,  the  contraction of
the PSD reportable segment and the continued positive impact of cost containment
measures.

Adjustment  of  Restructuring  Accrual:  During the first  quarter of 1997,  the
Company reversed an accrual of $75,000 made as part of the restructuring actions
taken in the fourth quarter of 1996. The year end accrual was revised to reflect
lower than  anticipated  costs  associated  with the  abandonment and subsequent
sublease of certain office space.

Loss on Disposition of Laboratory: During the first quarter of 1997, the Company
completed the sale of CAS to the employees of CAS for  $4,000,000 in cash,  CAS'
promissory notes for $3,219,000  ("CAS Notes") and a continuing  preferred stock
interest in CAS valued at $500,000. The Company paid $206,000 in cash to CAS for
retired  employee  contracts  and for  accelerated  vesting of stock options and
other non vested stock  rights.  In  anticipation  of completing  the sale,  the
Company  recognized  impairment  in  the  value  of  its  investment  in  CAS of
$3,327,000 at the end of 1996.  As a result of several pre closing  adjustments,
the Company  recognized an additional  loss on  disposition  of CAS in the first
quarter of 1997 of $333,000.

Gain on Sale of Assets:  During the first quarter of 1997, the Company completed
the sale of one of its landfill  gas-to-energy  projects,  including the related
leasehold production rights and associated machinery and equipment.  The Company
recognized a gain on disposition of the project in the first quarter of 1997, of
$826,000.

Income From Operations: Income from operations for the first nine months of 1998
was $2,901,000,  a 30.8% decrease  compared to $4,190,000  during the comparable
period last year. Income from operations,  as a percent of net revenue decreased
to 3.0% for the first nine months of 1998 from 5.1% in the comparable  period in
1997.

Interest Income:  The Company recorded  interest income of $444,000 in the first
nine months of 1998  compared to $364,000 in the first nine months of 1997.  The
increase  in interest  income in the first nine  months of 1998  compared to the
first nine  months of 1997 was  primarily  due to the  recognition  of  interest
income on the CAS Notes.

Interest Expense. The Company incurred interest expense of $891,000 in the first
nine months of 1998 compared to $923,000 in the first nine months of 1997.


                                       13
<PAGE>


Quarters Ended September 30, 1998 and 1997

Net Revenue.  Net revenue for the quarter  ended  September  30,  1998,  totaled
$35,631,000,  a 19.2%  increase  from net revenue of  $29,899,000  for the third
quarter of 1997.  The  increase  in net  revenue  was  primarily  due to a 38.3%
increase in net revenue  from the EOC  reportable  segment as the demand for its
services  continues to expand.  Net revenue from the PSD reportable  segment was
relatively unchanged with a 1.0% increase.

Direct  Expenses.  Direct  expenses for the quarter  ended  September  30, 1998,
totaled $21,809,000,  a 37.0% increase from $15,916,000 during the third quarter
of 1997. As a percentage of net revenue, direct expenses increased from 53.2% in
the third  quarter of 1997 to 61.2% in the third  quarter of 1998.  The increase
was due in large part to a shift in business mix  resulting  from the  continued
expansion of the EOC reportable segment.

Indirect  Expenses.  Indirect  expenses for the quarter ended September 30, 1998
totaled  $12,254,000,  a 0.5%  increase from  indirect  expenses of  $12,194,000
during the third  quarter of 1997.  As a  percentage  of net  revenue,  indirect
expenses decreased from 40.8% in the third quarter of 1997 to 34.4% in the third
quarter  of  1998.  The  decrease  was due in part to the  above-noted  shift in
business mix resulting from the expansion of the EOC reportable  segment and the
continued positive impact of cost containment measures.

Income From  Operations.  Income from operations for the quarter ended September
30, 1998, was  $1,568,000,  a 12.4% decrease  compared to $1,789,000  during the
third  quarter of 1997.  Income  from  operations,  as a percent of net  revenue
decreased  to 4.4% in the third  quarter  of 1998  from  6.0% in the  comparable
period in 1997.

Interest Income. The Company recorded interest income of $125,000 in the quarter
ended September 30, 1998 compared to $145,000 in the third quarter of 1997.

Interest  Expense.  The  Company  incurred  interest  expense of $294,000 in the
quarter  ended  September  30, 1998 compared to $275,000 in the third quarter of
1997.

LIQUIDITY AND CAPITAL RESOURCES

During  the  first  nine  months  of  1998,  the  Company's  uses  of  cash  for
non-operating  activities primarily consisted of repayment of debt in the amount
of  $1,800,000  and  additions  to  property  and  equipment  in the  amount  of
$2,968,000; mainly computers, field equipment and developed leachate evaporation
system (LES)  projects.  Net cash  provided by operating  activities  during the
period was $3,228,000.

In  conjunction  with the  acquisition  of OWT in the first quarter of 1996, the
Company  entered into a $20,000,000  secured credit  agreement with its existing
commercial  bank (the "Credit  Agreement"),  replacing its previous  $10,000,000
unsecured  line  of  credit.  Under  the new  agreement,  the  Company  borrowed
$10,000,000  on a term loan basis with  interest at a managed rate not to exceed
the prime rate.  Principal is to be  amortized  over seven years with any unpaid
amounts due and payable on June 30, 2001. In April 1997,  following the infusion
of cash  upon  the sale of  Columbia  Analytical  Services,  Inc.,  the  Company
prepaid, on an accelerated basis,  $3,000,000 of the then outstanding  principal
balance of the term loan. The remaining  $10,000,000  under the Credit Agreement
is available for working capital  purposes in the form of a line of credit (with
up to $5,000,000  also being available for non-working  capital  purposes).  The
line of credit component of the Credit

                                       14
<PAGE>


Agreement expires on November 30, 1998. The Company expects to renew the line of
credit  component of the Credit  Agreement prior to its  expiration.  The Credit
Agreement  contains  provisions with respect to the payment of dividends and the
level of capital expenditures and requires the maintenance of specific levels of
working capital, tangible net worth and continued quarterly profitability.

The Company  believes that its cash on hand and cash generated from  operations,
together  with its  available  bank  financing  will be  sufficient  to meet the
Company's capital needs for at least the next twelve months.


                                       15
<PAGE>



                                      EMCON

                            PART II OTHER INFORMATION

Items 1. - 5.     Not applicable.

Item 6.           Exhibits and Reports

      (a)         Exhibits - See Index to Exhibits on Page 18

      (b)  Reports  on Form 8-K - No  reports  on Form 8-K were  filed  with the
      Securities and Exchange  Commission during the quarter ended September 30,
      1998.





                                       16

<PAGE>


                                      EMCON


                                   SIGNATURES

Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.



Date:  October 31, 1998                    EMCON


                                           \s\  R. Michael Momboisse
                                           -------------------------------------
                                           R. MICHAEL MOMBOISSE
                                           Chief Financial Officer,
                                           Vice President - Legal, and Secretary
                                            (Duly authorized and principal
                                             financial and accounting officer)



                                       17
<PAGE>


                                INDEX TO EXHIBITS
                                                                   Sequentially
   Exhibit                                                           Numbered
   Number                                                              Page
--------------                                                     -------------

     2.1       Stock Purchase  Agreement  dated January 30, 1996,        *
               among Organic  Waste  Technologies,  Inc. ("OWT"),
               Registrant and the selling shareholders and option
               holders of OWT,  incorporated  by  reference  from
               Exhibit  2.1 of the  Current  Report  on Form  8-K
               dated March 14, 1996, (the "March 1996 8-K").

     2.2       Asset  Purchase   Agreement  between  Yolo  Energy        *
               Partners,  Inc.,  Yolo  Landfill Gas  Corporation,
               EMCON,  Yolo Neo LLC,  and  Minnesota  Methane LLC
               dated December 31, 1996, incorporated by reference
               from  Exhibit  10.20 of the Annual  Report on Form
               10-K for the fiscal year ended  December  31, 1996
               (the "1996 10-K").

     2.3       Acquisition Agreement between EMCON and its wholly        *
               owned    subsidiary,    Monterey    Landfill   Gas
               Corporation,  and Biomass Energy Partners V, L.P.,
               dated  March 6, 1997,  incorporated  by  reference
               from Exhibit 10.22 of the 1996 10-K.

     2.4       Stock Purchase Agreement dated April 4, 1997 among        *
               Registrant,  Columbia  Analytical  Services,  Inc.
               (`CAS"),  Northwest  Trust as  trustee  of the CAS
               Employee Stock  Ownership Trust and certain senior
               management  employees  of  CAS,   incorporated  by
               reference  from  Exhibit  2.4 of the  Registrant's
               Quarterly  Report  on Form  10-Q  for  the  fiscal
               quarter  ended  March 31,  1997 (the  "March  1997
               10-Q").

     2.5       Stock  Purchase  Agreement  dated  April 30,  1997        *
               among  Registrant,  OWT,  National Earth Products,
               Inc. ("NEP") and the selling  stockholders of NEP,
               incorporated  by reference from Exhibit 2.5 of the
               March 1997 10-Q.

     2.6       Agreement   and  Plan  of   Reorganization   among         *
               Registrant,  Advanced Analytical  Solutions,  Inc.
               ("A2S") and certain  other  parties dated April 3,
               1998,  incorporated  by reference from Exhibit 2.6
               of the  Quarterly  Report  on  Form  10-Q  for the
               fiscal  quarter  ended  March 31, 1998 (the "March
               1998 10-Q").

     3.1       Articles    of    Incorporation,    as    amended,         *
               incorporated  by reference from Exhibit 3.1 of the
               Registrant's  Registration  Statement  on Form S-1
               (File No. 33-16337)  effective  September 16, 1987
               (the "Form S-1 Registration Statement").

     3.2       Certificate  of Amendment of Restated  Articles of         *
               Incorporation   as   filed   on  May   24,   1988,
               incorporated  by reference from Exhibit 3.2 of the
               Annual  Report  on Form 10-K for the  fiscal  year
               ended December 31, 1988 (the "1988 10-K").

     3.3       Certificate  of Amendment of Restated  Articles of         *
               Incorporation   as   filed   on  June   4,   1991,
               incorporated  by reference from Exhibit 4.1 of the
               Quarterly  Report  on Form  10-Q  for  the  fiscal
               quarter  ended  June  30,  1991  (the  "June  1991
               10-Q").

                               18
<PAGE>





                                                                    Sequentially
   Exhibit                                                            Numbered
   Number                    INDEX TO EXHIBITS (Continued)              Page
--------------                                                      ------------

     3.4       Bylaws, as amended, incorporated by reference from         *
               Exhibit 4.2 of the June 1991 10-Q.

    10.1       EMCON  1986   Incentive   Stock  Option  Plan  and        *(1)
               Amendment,  incorporated by reference from Exhibit
               10.15 of the Form S-1 Registration Statement.

    10.2       Form of Agreement pursuant to Salary  Continuation        *(1)  
               Plan, incorporated by reference from Exhibit 10.17
               of the Form S-1 Registration Statement.

    10.3       Schedule identifying Agreements pursuant to Salary        *(1)
               Continuation  Plan between  Registrant and certain
               employees,  incorporated by reference from Exhibit
               10.3 of the  Registrant's  Annual  Report  on Form
               10-K for the fiscal year ended  December  31, 1997
               (the "1997 10-K").

    10.4       Form of Indemnity Agreement between the Registrant         *
               and  each  of  the   Registrant's   officers   and
               directors,  incorporated by reference from Exhibit
               10.20 of the  Registrant's  Annual  Report on Form
               10-K for the fiscal year ended  December  31, 1988
               (the "1988 10-K").

    10.5       EMCON  1988   Stock   Option   Plan,   amended  by        *(1)
               shareholder  approval  on May  25,1994,  including
               form  of  Nonqualified   Stock  Option   Agreement
               (Outside  Directors),  incorporated  by  reference
               from Exhibit 10.9 of Registrant's Quarterly Report
               on Form 10-Q for the fiscal quarter ended June 30,
               1994 (the "June 30, 1994 10-Q").

    10.6       EMCON Employee Stock Purchase Plan incorporated by        *(1)
               reference  from Exhibit 10.10 of the  Registrant's
               Quarterly  Report  on Form  10-Q  for  the  fiscal
               quarter ended June 30, 1995.

    10.7       EMCON  Restricted   Stock  Plan   incorporated  by        *(1)
               reference  from Exhibit 10.15 of the Annual Report
               on Form 10-K for the fiscal  year  ended  December
               31, 1990.

    10.8       EMCON Deferred Compensation Plan effective January        *(1)
               1, 1994,  incorporated  by reference  from Exhibit
               10.12 of the  Registrant's  Annual  Report on Form
               10-K for the fiscal year ended  December  31, 1993
               (the "1993 10-K").

    10.9       Trust    Agreement   for   the   EMCON    Deferred        *(1)
               Compensation  Plan and  Salary  Continuation  Plan
               Trust dated February 19, 1994,  between Registrant
               and  Wells  Fargo  Bank,   N.A.   incorporated  by
               reference from Exhibit 10.13 of the 1993 10-K.

    10.10      Agreement  between Eugene M. Herson and Registrant        *(1)
               dated November 30, 1995, incorporated by reference
               from Exhibit 10.21 of  Registrant's  Annual Report
               on Form 10-K for the fiscal  year  ended  December
               31, 1995 (the "1995 10-K").

                               19
<PAGE>





                                                                    Sequentially
   Exhibit                                                            Numbered
   Number                    INDEX TO EXHIBITS (Continued)               Page
--------------                                                      ------------

    10.12      Credit  Agreement  between The Bank of California,          *
               N.A.  and  Registrant  dated  February  29,  1996,
               incorporated by reference from Exhibit 10.2 of the
               March 1996 8-K.

    10.13      Security    Agreement    between   The   Bank   of          *
               California, N.A. and Registrant dated February 29,
               1996,  incorporated by reference from Exhibit 10.3
               of the March 1996 8-K.

    10.14      Pledge  Agreement  between The Bank of California,          *
               N.A.  and  Registrant  dated  February  29,  1996,
               incorporated by reference from Exhibit 10.4 of the
               March 1996 8-K.

    10.15      Eurodollar Rate Option Agreement  between The Bank          *
               of California,  N.A. and Registrant dated February
               29, 1996,  incorporated  by reference from Exhibit
               10.5 of the March 1996 8-K.

    10.16      Fixed Rate  Amortization  Option Agreement between          *
               The Bank of California,  N.A. and Registrant dated
               February 29, 1996,  incorporated by reference from
               Exhibit 10.6 of the March 1996 8-K.

    10.17      Note  Agreement  among the  Registrant,  OWT,  and          *
               certain   employees  of  OWT  ,   incorporated  by
               reference from Exhibit 10.1 of the March 1996 8-K.

    10.18      Rescission   and   Reformation   Agreement   dated          *
               effective  November 1, 1996 among EMCON,  OWT, and
               certain   employees   of  OWT,   incorporated   by
               reference from Exhibit 10.18 of the 1996 10-K.

    10.19      New Note  Agreement  dated  effective  November 1,          *
               1996 among  EMCON,  OWT and certain * employees of
               OWT,  incorporated by reference from Exhibit 10.19
               of the 1996 10-K.

    10.20      Second   Amendment  to  Credit   Agreement   dated          *
               effective  January  27, 1997 among EMCON and Union
               Bank of California,  N.A.  (formerly  known as The
               Bank  of  California,   N.A.),   incorporated   by
               reference from Exhibit 10.21 of the 1996 10-K.

    10.21      Third   Amendment   to  Credit   Agreement   dated          *
               effective  March 27,  1997  among  EMCON and Union
               Bank of California,  N.A.  (formerly  known as The
               Bank  of  California,   N.A.),   incorporated   by
               reference from Exhibit 10.23 of the 1996 10-K.

    10.22      Convertible  Notes  dated April 30, 1997 issued by          *
               EMCON to Dennis Grimm and Charles  Gearhart in the
               principal  amounts of $400,798.40 and $399,201.60,
               respectively,   incorporated   by  reference  from
               Exhibit 10.22 of the March 1997 10-Q.

                               20
<PAGE>



                                                                    Sequentially
   Exhibit                                                             Numbered
   Number                    INDEX TO EXHIBITS (Continued)               Page
--------------                                                      ------------

    10.23      Lease  Agreement  dated  April  4,  1997,  between         *  
               EMCON  and  Columbia  Analytical  Services,  Inc.,
               incorporated  by reference  from Exhibit  10.23 of
               the March 1997 10-Q.

    10.24      Amendment  1997-I to EMCON  Deferred  Compensation        *(1)
               Plan   dated   effective    February   22,   1997,
               incorporated  by reference  from Exhibit  10.24 of
               the Registrant's Quarterly Report on Form 10-Q for
               the fiscal  quarter ended June 30, 1997 (the "June
               30, 1997 10-Q").

    10.25      Fourth   Amendment  to  Credit   Agreement   dated         *
               effective June 24, 1997 among EMCON and Union Bank
               of  California,  N.A.,  incorporated  by reference
               from Exhibit 10.25 of the June 30, 1997 10-Q.

    10.26      Amended and Restated  Agreement  between Eugene M.        *(1)
               Herson  and  Registrant  dated  November  3, 1997,
               incorporated  by reference  from Exhibit  10.26 of
               the 1997 10-K.

    10.27      Amended and Restated  Agreement between R. Michael        *(1)
               Momboisse and  Registrant  dated November 3, 1997,
               incorporated  by reference  from Exhibit  10.27 of
               the 1997 10-K.

    10.28      Deferred  Compensation  Plan, Amended and Restated        *(1)
               effective   January  1,  1998,   incorporated   by
               reference from Exhibit 10.28 of the 1997 10-K.

    10.29      Registration  Rights  Agreement among  Registrant,         *
               and the former  shareholders of A2S dated April 3,
               1998, incorporated by reference from Exhibit 10.29
               of the March 1998 10-Q.

    10.30      Secured  Promissory  Note  of  Timothy  M.  Keaten         *
               dated April 3, 1998,  in the  principal  amount of
               $225,000,  incorporated  by reference from Exhibit
               10.30 of the March 1998 10-Q.

    10.31      EMCON 1998 Stock Option Plan,  with  standard form         *
               of Incentive Stock Option Agreement, Non-Statutory
               Stock Option  Agreement  and  Non-Statutory  Stock
               Option   Agreement   (outside   Director   Option)
               attached,  incorporated  by reference from Exhibit
               10.31 of the Registrant's Quarterly Report on Form
               10-Q for the fiscal  quarter  ended June 30,  1998
               (the "June 30, 1998 10-Q").

    10.32      Sixth   Amendment   to  Credit   Agreement   among         *
               Registrant and Union Bank of California dated June
               1, 1998,  incorporated  by reference  from Exhibit
               10.32 of the June 30, 1998 10-Q.

                               21
<PAGE>



                                                                    Sequentially
   Exhibit                                                             Numbered
   Number                   INDEX TO EXHIBITS (Continued)                Page
--------------                                                      ------------

    10.33      Seventh   Amendment  to  Credit   Agreement  among         23
               Registrant  and  Union  Bank of  California  dated
               August 31, 1998.

     27        Financial Data Schedule, included herein.                  28
    
 *  Incorporated by reference

(1)  Management  contract or  compensatory  plan or  arrangement  required to be
     filed as an exhibit to this form pursuant to Item 14(c) of the instructions
     to Form 10-K.



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