SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
            ----------------------------------------------------

                                    FORM 10-K

(mark one)
[  X ] Annual Report Pursuant to Section 13 or 15(d) of the Securities
       Exchange Act of 1934 for the fiscal year ended April 1, 2000

[    ] Transition Report Pursuant to Section 13 or 15(d) of the Securities
       Exchange Act of 1934

                          Commission file number 1-9549

                              THERMO TERRATECH INC.
             (Exact name of Registrant as specified in its charter)

Delaware                                         04-2925807
(State or other jurisdiction of
incorporation or organization)        (I.R.S. Employer Identification No.)

81 Wyman Street, P.O. Box 9046
Waltham, Massachusetts                                  02454-9046
(Address of principal executive offices)                (Zip Code)

           Registrant's telephone number, including area code: (781) 622-1000

           Securities registered pursuant to Section 12(b) of the Act:

        Title of each class        Name of each exchange on which registered
 Common Stock, $.10 par value            American Stock Exchange

           Securities registered pursuant to Section 12(g) of the Act:
                                      None

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 and (2) has been subject to the filing requirements for
at least the past 90 days. Yes [ X ] No [ ]

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of the Registrant's knowledge, in definitive proxy or information
statements incorporated by reference into Part III of this Form 10-K or any
amendment to this Form 10-K. [ ]

The aggregate market value of the voting stock held by nonaffiliates of the
Registrant as of April 28, 2000, was approximately $16,872,000.

As of April 28, 2000, the Registrant had 18,956,855 shares of Common Stock
outstanding.

                       DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant's Fiscal 2000 Annual Report to Shareholders for the
year ended April 1, 2000, are incorporated by reference into Parts I and II.

The information required by Item III of Form 10-K will be filed as an amendment
to this Form 10-K no later than 120 days after April 1, 2000, and such
information is incorporated by reference from such filing.

<PAGE>


                                     PART I

Item 1.  Business

(a)   General Development of Business

      Thermo TerraTech Inc. (the Company or the Registrant) provides industrial
outsourcing services and manufacturing support encompassing a broad range of
specializations.  The Company operates in four segments:  environmental-
liability management, engineering and design, laboratory testing, and metal
treating.

      Thermo Electron Corporation, the majority owner of the Company, has
announced a proposed reorganization involving certain of Thermo Electron's
subsidiaries, including the Company. Under this plan, the Company and its
subsidiaries, ThermoRetec Corporation and The Randers Killam Group Inc., would
be merged into Thermo Electron. As a result, all three companies would become
privately held subsidiaries of Thermo Electron. The mergers of ThermoRetec and
Killam were effective in June and May 2000, respectively. The public
shareholders of ThermoRetec and Killam received $7.00 and $4.50 per share,
respectively, in cash in exchange for their shares. The merger between the
Company and Thermo Electron is expected to be complete in the third quarter of
calendar 2000. The public shareholders of the Company are expected to receive
common stock in Thermo Electron in exchange for their shares. The number of
Thermo Electron shares to be issued to Thermo TerraTech minority shareholders
will be determined at the time of the merger transaction, according to the
following conditions: If during the 20 trading days immediately prior to the
effective date of the merger the average closing price of Thermo Electron common
stock is less than $18.75, Thermo TerraTech shareholders would receive common
stock worth the equivalent of $7.50 per share of Thermo TerraTech common stock.
However, Thermo Electron may elect to terminate the agreement if it would be
required to issue 1.8 million or more shares of Thermo Electron common stock. If
the average closing price of Thermo Electron common stock is between $18.75 and
$23.125, each share of Thermo TerraTech common stock would be exchanged for .4
shares of Thermo Electron common stock. If the average closing price of Thermo
Electron common stock is greater than $23.125, Thermo TerraTech shareholders
would receive Thermo Electron common stock worth the equivalent of $9.25 per
share of Thermo TerraTech common stock. The completion of this transaction is
subject to numerous conditions, as outlined in Note 15 to Consolidated Financial
Statements in the Registrant's Fiscal 2000* Annual Report to Shareholders, which
statements are incorporated herein by reference.

      In May 1999, the Company announced the planned sale of several businesses
by its subsidiaries. In connection with these proposed sales, the Company
incurred pretax charges totaling approximately $59 million in fiscal 2000 and
expects to incur an additional $2 million in fiscal 2001. On January 31, 2000,
Thermo Electron announced that it plans to sell all of the businesses of the
Company. This action is part of a major reorganization plan under which Thermo
Electron will spin in, spin off, and sell various businesses to focus solely on
its core measurement and detection instruments business.

      The Environmental-liability Management segment includes the Company's
ThermoRetec subsidiary, which is a national provider of environmental-liability
and resource-management services. Through a nationwide network of offices,
ThermoRetec historically offered these and related consulting services in four
areas: consulting and engineering, nuclear remediation, soil remediation, and
fluids recycling. In February 2000, ThermoRetec entered into a letter of intent
to sell five of its six remaining soil-recycling facilities. The transaction is
expected to be completed before the end of July 2000, although there can be no
assurance that ThermoRetec will complete this sale. In March 2000, ThermoRetec
sold its sixth soil-recycling facility. As of April 1, 2000, the Company owned
70% of ThermoRetec's outstanding common stock. As noted above, ThermoRetec has
become a privately held subsidiary, jointly owned by the Company and Thermo
Electron. The Company's majority-owned Thermo EuroTech N.V. subsidiary, located
in the Netherlands, specializes in converting "off-spec" and contaminated
petroleum fluids into

--------------------
*  References to fiscal 2000, 1999, and 1998 herein are for the fiscal years
   ended April 1, 2000, April 3, 1999, and April 4, 1998, respectively.


                                       2
<PAGE>

useable oil products. Thermo EuroTech also provides in-plant waste management
and recycling services through its Ireland-based Green Sunrise Holdings Ltd.
subsidiary. In August 1999, Green Sunrise acquired the outstanding stock of
Dempsey Drums Limited, an Ireland-based service provider specializing in the
supply, disposal, and reconditioning of steel and plastic drums and other
specialized containers. On May 3, 2000, the Company entered into a letter of
intent to sell the outstanding stock of Green Sunrise. As of April 1, 2000, the
Company owned 88% of Thermo EuroTech's outstanding common stock.

      The Engineering and Design segment includes the Company's Killam
subsidiary, which historically provided comprehensive engineering and
outsourcing services in four areas: water and wastewater treatment, process
engineering and construction, highway and bridge engineering, and infrastructure
engineering. In January 2000, Killam sold its Randers division, a process
engineering and construction business. In April 2000, Killam sold the assets of
its BAC Killam Inc. subsidiary, a highway and bridge engineering business. As of
April 1, 2000, the Company owned approximately 95% of Killam's outstanding
common stock. As noted above, Killam has become a privately held subsidiary,
jointly owned by the Company and Thermo Electron. This segment also includes the
Company's wholly owned Normandeau Associates Inc. subsidiary, which provides
consulting services that address natural resource management issues.

      The Company's wholly owned Thermo Analytical Inc. subsidiary, which
represents the Laboratory Testing segment, operates analytical laboratories that
provide environmental- and pharmaceutical-testing services, primarily to
commercial clients throughout the U.S.

      The Metal Treating segment performs metallurgical processing services
using thermal-treatment equipment at locations in California, Minnesota, and
Wisconsin. The Company sold the businesses comprising this segment in June 2000.

      The Company was incorporated on May 30, 1986, as an indirect, wholly owned
subsidiary of Thermo Electron. As of April 1, 2000, Thermo Electron owned
16,605,286 shares of the Company's common stock, representing 88% of such stock
outstanding. Thermo Electron develops, manufactures, and sells measurement and
detection instruments used in virtually every industry to monitor, collect, and
analyze data that provide knowledge for the user. For example, Thermo Electron's
powerful analysis technologies help researchers sift through data to unlock the
mysteries of DNA or develop new drugs; allow manufacturers to fabricate
ever-smaller components required to carry greater amounts of information,
faster; or monitor and control industrial processes on-line to ensure that
critical quality standards are met efficiently.

Forward-looking Statements

      Forward-looking statements, within the meaning of Section 21E of the
Securities Exchange Act of 1934, are made throughout this Annual Report on Form
10-K. For this purpose, any statements contained herein that are not statements
of historical fact may be deemed to be forward-looking statements. Without
limiting the foregoing, the words "believes," "anticipates," "plans," "expects,"
"seeks," "estimates," and similar expressions are intended to identify
forward-looking statements. There are a number of important factors that could
cause the results of the Company to differ materially from those indicated by
such forward-looking statements, including those detailed under the heading
"Forward-looking Statements" in the Registrant's Fiscal 2000 Annual Report to
Shareholders, which statements are incorporated herein by reference.

(b)   Financial Information About Segments

      Financial information concerning the Company's segments is summarized in
Note 13 to Consolidated Financial Statements in the Registrant's Fiscal 2000
Annual Report to Shareholders, which information is incorporated herein by
reference.

                                       3
<PAGE>


(c)   Description of Business

      (i)  Principal Services and Products

Environmental-liability Management

      The Company provides environmental consulting and remediation construction
management to clients in the transportation, refining, chemical, wood-treating,
gas, and electric utility industries across the nation. The Company offers a
broad array of remedial solutions to help clients manage problems associated
with environmental compliance, resource management, and the remediation of
industrial sites contaminated with various wastes and residues. The Company
provides particular expertise in bioremediation and in managing wastes from
manufactured-gas plants, refineries, and railroad properties.

      The Company also performs cleanups of hazardous waste sites for government
and industry as a prime construction contractor and completes predesigned
remedial action contracts at sites containing hazardous, toxic, and radioactive
wastes. Under contracts with federal and state governments, and other public and
private sector clients, the Company also provides project management and
construction services for the remediation of hazardous and nonhazardous wastes.
Most of this contract work is obtained through a bid process, with the job being
awarded to the best qualified bidder.

      In addition, the Company helps public utilities, government institutions,
and Fortune 500 companies develop and implement management and computer-based
systems that aid in the collection and application of environmental and
resource-management data. By helping to establish or improve a customer's
environmental-compliance program, the Company's customized services promote and
support the integration of environmental-management functions with everyday
business activities. The Company's services help multinational companies
accurately estimate and control the cost of their environmental-compliance and
health and safety efforts. The Company also develops measurement systems that
track clients' progress toward their stated environmental performance goals.

      The Company provides services to remove radioactive contaminants from
sand, gravel, and soil, as well as health physics services, radiochemistry
laboratory services, radiation dosimetry services, radiation-instrument
calibration and repair services, and radiation-source production. As part of its
radiation and nuclear/health physics services business, the Company provides
site surveys for radioactive materials and on-site samples, as well as analysis
in support of decontamination programs and dosimetry services to measure
personnel exposure. In addition, using its proprietary segmented-gate system
technology, the Company removes radioactive contaminants from sand, gravel, and
soil. A substantial part of the Company's health physics services has been
performed under the U.S. Department of Energy's remedial action programs.

      The Company designs and operates facilities for the remediation of
nonhazardous soil. The Company's soil-recycling centers are environmentally
secure facilities for receiving, storing, and processing petroleum-contaminated
soils. Each site consists principally of a soil-remediation unit and a
soil-storage area. The Company currently provides soil-remediation services at
facilities in California, Oregon, Washington, Maryland, and New York. During
fiscal 1999, the Company announced plans to close two soil-recycling facilities,
of which one was closed in March 1999 and the other was sold in March 2000. In
addition, during fiscal 2000, ThermoRetec announced plans to sell three
additional soil-recycling facilities. In February 2000, ThermoRetec signed a
letter of intent to sell its five remaining soil-recycling facilities, including
the three announced in May 1999. The transaction is expected to be completed
before the end of July 2000, although there can be no assurance that ThermoRetec
will complete this sale.

      The market for remediation of petroleum-contaminated soils, as with many
other waste markets, was created by environmental regulations. The market for
soil-remediation services has been driven largely by state programs to enforce
the Environmental Protection Agency's (EPA's) underground storage tank (UST)
regulations and to fund cleanups. UST compliance requirements and attendant
remediation costs are often beyond the financial capabilities of

                                       4
<PAGE>

individuals and smaller companies. To address this problem, some states
established tax-supported trust funds to assist in the financing of UST
compliance and remediation. Many states have realized that the number of sites
requiring remediation and the costs of compliance are substantially higher than
were originally estimated. As a result, several states have significantly
reduced compliance requirements and altered regulatory approaches and standards
in order to reduce the costs of cleanup. More lenient regulatory standards,
reduced enforcement, and uncertainty with respect to such changes have already
resulted in lower levels of cleanup activity in most states where the Company
conducts business, which had a material adverse effect on the Company's business
in recent years. Although the Company expects this market to remain viable for
some time after April 1, 2000, there can be no assurance that this business will
not decline in future years.

      The Company offers a full spectrum of environmental services related to
managing and recycling nonhazardous, liquid, and solid materials generated by
business and industry. The Company's client base is largely public retail and
industrial businesses, but also includes municipalities, public utilities,
railroads, the mining industry, and government agencies. The materials managed
by the Company for its customers primarily are used oils and oil-contaminated
waters, which are continuously generated as part of the customers' operations.
As such, the Company provides services for its customers on a recurring basis.
The Company processes the materials it collects into products for resale and/or
recycling, such as fuel, glycol, steel, and clean water. The Company has
expanded its services to include a variety of field technical services,
including on-site waste sampling and testing, emergency response, and tank
cleaning.

      Thermo EuroTech specializes in processing "off-spec" mixtures of oil that
contain water, ash, and sediment into commercially tradable end products used in
blending. The end products of this process are commercial grade oils that can be
blended to make diesel fuels and marine fuels or be used as a feed material.
Thermo EuroTech's North Refinery facility has historically received a large
percentage of its oil feedstock from the former Soviet Union. North Refinery no
longer receives any oil from that nation, due to political and economic changes
that have made the transportation of waste oil difficult. To overcome this loss
of supply, Thermo EuroTech has taken steps to replace and diversify its
feedstock suppliers. In addition, Thermo EuroTech has applied to Dutch
authorities for licenses to broaden the variety of waste streams that could be
treated at North Refinery. North Refinery may experience future disruptions in
deliveries. Any disruptions in supply could have a material adverse effect on
the Company's results of operation. In addition, North Refinery has received a
one-year exemption from the environmental authorities in the Netherlands and the
United Kingdom allowing it to export refined oil, which would otherwise be
regulated as "waste" under the environmental regulations of those countries. If
North Refinery is unable after that time to qualify its exported oil as
non-waste quality oil, or if North Refinery is unable to extend the length of
its exemption, the Company's results of operations could be materially adversely
affected.

      Thermo EuroTech also provides in-plant waste management and recycling
services through its Ireland-based Green Sunrise subsidiary. In August 1999,
Green Sunrise acquired the outstanding stock of Dempsey Drums Limited, an
Ireland-based service provider specializing in the supply, disposal, and
reconditioning of steel and plastic drums and other specialized containers. On
May 3, 2000, the Company entered into a letter of intent to sell the outstanding
stock of Green Sunrise.

      During fiscal 2000, 1999, and 1998, the Company derived revenues of $166.2
million, $159.1 million, and $141.1 million, respectively, from
environmental-liability management services.


                                       5
<PAGE>

Engineering and Design

      The Company historically provided comprehensive engineering and
outsourcing services in such areas as water and wastewater treatment, process
engineering and construction, highway and bridge engineering, and infrastructure
engineering. In January 2000, Killam sold its Randers division, a process
engineering and construction business. In April 2000, Killam sold the assets of
its BAC Killam Inc. subsidiary, a highway and bridge engineering business. A
substantial portion of the Company's engineering and design services sales are
made to existing customers on a repeat basis. Engineering and design services
are often performed as multiyear studies. In addition to federal, state, and
local governments, customers include public utilities, waste management
companies, oil refineries, mining companies, architectural and engineering
firms, and a variety of service companies involved with real estate
transactions.

      The Company specializes in the design, planning, and construction
observation of municipal and privately owned water treatment plants, wastewater
treatment plants, and hazardous wastewater facilities. The Company provides
full-service contract operations to plant owners in the public and private
sectors. These services facilitate regulatory compliance; optimize day-to-day
plant operations; reduce costs; provide competent, experienced personnel; and
promote good community relations.

      Until the January 2000 sale of the Randers division, the Company provided
design engineering, project management, and construction services for industrial
clients in the manufacturing, pharmaceutical, and chemical-processing
industries, principally in the Mid-West, Massachusetts, and West Virginia.

      In addition, the Company provides a broad range of consulting services,
which address transportation planning and design, and transportation and
environmental consulting, professional engineering, and architectural services.

      During fiscal 2000, 1999, and 1998, the Company derived revenues of $79.6
million, $91.8 million, and $84.6 million, respectively, from engineering and
design services.

Laboratory Testing

      The Company provides comprehensive laboratory-based services for the
environmental and pharmaceutical industries. Analytical laboratory services
consist of a comprehensive range of analytical tests to detect and measure
organic contaminants and inorganic contaminants in samples of soil, water, air,
industrial wastes, and biological materials. The Company also provides testing
services for major pharmaceutical companies in support of new healthcare drug
development.

      During fiscal 2000, 1999, and 1998, the Company derived revenues of $44.8
million, $40.5 million, and $37.5 million, respectively, from laboratory testing
services.

Metal Treating

      Prior to June 2000, the Company performed metallurgical processing
services using thermal-treatment equipment at locations in California,
Minnesota, and Wisconsin. Through its Holcroft Division, which was sold in
October 1997, the Company designed, manufactured, and installed
computer-controlled, custom-engineered, thermal-processing systems used to treat
primary metals and metal parts. The Company sold the remaining businesses
comprising this segment in June 2000.

      During fiscal 2000, 1999, and 1998, the Company derived revenues of $17.2
million, $19.3 million, and $36.6 million, respectively, from metal treating
services and process systems.


                                       6
<PAGE>

      (ii) New Products

      The Company has made no commitments to new products that would require the
investment of a material amount of the Company's assets.

      (iii)Raw Materials

      Since the Company's business is primarily service oriented, it does not
involve the processing of raw materials and is not dependent on fluctuations in
the supply or price of raw materials, except as described above. To date, the
Company has not experienced any difficulty in obtaining any of the materials or
components used in its operations and does not foresee any such difficulty in
the future. The Company has multiple sources for all of its significant raw
material needs.

      Prior to fiscal 1996, a large percentage of oil feedstock at Thermo
EuroTech's North Refinery division came from the former Soviet Union. Thermo
EuroTech no longer receives any oil from that nation as a result of political
and economic changes that make transportation of waste oil difficult. To
overcome this loss of supply, Thermo EuroTech has taken steps to replace and
diversify its feedstock suppliers. However, no assurance can be given that it
will not experience future disruptions in deliveries.

      (iv) Patents, Licenses, and Trademarks

      The Company currently owns or has rights under licenses to a number of
U.S. patents. Although the Company believes that patent protection provides it
with competitive advantages with respect to certain portions of its business and
will continue to seek patent protection when appropriate, the Company also
believes that its business depends primarily upon trade secrets and the
technical and marketing expertise of its personnel.

      (v)  Seasonal Influences

      A majority of the Company's businesses experience seasonal fluctuations. A
majority of the Company's soil-remediation sites, as well as the Company's
fluids-recycling sites, experience declines in revenues if severe weather
conditions occur. Site remediation work and certain environmental testing
services may decline in winter months as a result of severe weather conditions.
In Europe, Thermo EuroTech may experience a decline in the feedstock delivered
to and from its facilities during winter months due to frozen waterways.

      (vi) Working Capital Requirements

      In general, there are no special inventory requirements or credit terms
extended to customers that would have a material adverse effect on the Company's
working capital.

      (vii)Dependency on a Single Customer

      No single customer accounted for more than 10% of the Company's revenues
in any of the past three years.

                                       7
<PAGE>

      (viii)Backlog

      The Company's backlog of firm orders at fiscal year-end 2000 and 1999 was:

<TABLE>
<CAPTION>
<S>                                                                                        <C>       <C>
(In thousands)                                                                             2000      1999
-------------------------------------------------------------------------------------- --------- ---------

Environmental-liability Management                                                     $ 46,671    $47,635
Engineering and Design                                                                   58,465     62,136
Laboratory Testing                                                                        3,611      2,517
Metal Treating                                                                              300        300
                                                                                       --------   --------

                                                                                       $109,047   $112,588
                                                                                       ========   ========

      These amounts include the backlog of all of the Company's subsidiaries,
with the exception of soil-recycling, fluids-recycling, and in-plant waste
management and recycling services, which are provided on a current basis
pursuant to purchase orders. Included in the Company's backlog at fiscal
year-end 2000 and 1999 is the incomplete portion of contracts that are accounted
for using the percentage-of-completion method. The Company believes that
substantially all of the backlog at April 1, 2000, will be completed during
fiscal 2001. Certain of these orders are subject to cancellation by the customer
upon payment of a cancellation charge and all government contracts are subject
to termination at any time by the government without penalty.

      The Engineering and Design segment backlog at fiscal year-end 2000
includes $17,298,000 at the Company's BAC Killam subsidiary, which was sold in
April 2000. In addition, the businesses comprising the Metal Treating segment
were sold in June 2000.

      (ix) Government Contracts

      Approximately 8%, 6%, and 4% of the Company's revenues in fiscal 2000,
1999, and 1998, respectively, were derived from contracts or subcontracts with
the federal government that are subject to renegotiation of profits or
termination. The Company does not have any knowledge of threatened or pending
renegotiation or termination of any material contract or subcontract.

      (x)  Competition

      Many of the Company's businesses are engaged in highly competitive,
regional markets, with competition coming from numerous small firms offering
limited services, as well as much larger firms that offer an array of services.

Environmental-liability Management

      In the market for consulting and engineering services, the Company
competes with numerous regional and local companies as well as a number of
national remediation contractors. The Company competes primarily on the basis of
value, with the vast majority of the contracts it seeks awarded on the basis of
scope, effectiveness, and cost. Other competitive factors for the Company's
consulting and engineering businesses include: reputation; experience; breadth
and quality of services offered; and technical, managerial, and business
proficiency.

      The type of radiation and nuclear/health physics services offered by the
Company are also offered by many large national companies. The Company competes
primarily on the basis of its proprietary technology and price.

      Competition in the soil-remediation business is intense. The Company's
principal competitors are landfills, including major landfill companies. The
Company also currently competes with companies offering a wide range of disposal
options, including other fixed-site, thermal-treatment facilities, operators of
mobile thermal-treatment


                                       8
<PAGE>

facilities, bioremediation and vapor-extraction facilities, and, in certain
states, with asphalt plants and brick kilns that use the contaminated soil in
their production processes. Competition in the soil-remediation market has
always been highly localized, consisting mostly of single-site or single-unit
operators. Competitive conditions limit the prices charged by the Company in
each local market for soil-remediation services. Pricing is therefore a major
competitive factor for the Company. The Company believes competition and price
pressure will remain intense for the foreseeable future.

      Competition in the fluids recycling market is highly fragmented and ranges
in size from small, under-capitalized private enterprises to larger national
public companies. At both ends of this spectrum, the industry continues to
consolidate and restructure. The Company competes primarily on the basis of
quality and price.

      Thermo EuroTech faces competition for oil from other oil processors and
blenders and from a company with a similar distillation technology in Italy. The
market for blending oils is very large and oils such as Thermo EuroTech's end
products represent a very small percentage of the total market. Green Sunrise is
the leading integrated service provider in an emerging, still fragmented market.
The Company believes that no one competitor offers Green Sunrise's complete line
of services and no single firm is dominant in any of Green Sunrise's primary
service areas. Thermo EuroTech competes primarily on the basis of price.

Engineering and Design

      The Company's engineering and design businesses are engaged in highly
competitive markets in all of its service areas. These markets tend to be
regional. In its geographic service area, competition consists of small, one- to
three-person firms offering a limited scope of services, as well as much larger
firms that may be regional, national, or international in the scope of services
they offer. The principal competitive factors for the Company are: reputation;
experience; price; breadth and quality of services offered; and technical,
managerial, and business proficiency.

Laboratory Testing

      Hundreds of independent analytical testing laboratories and consulting
firms compete for business nationwide. Many of these firms use equipment and
processes similar to those of the Company. Competition is based not only on
price, but also on reputation for accuracy, quality, and the ability to respond
rapidly to customer requirements. In addition, many industrial companies have
their own in-house analytical testing capabilities. The Company believes that
its competitive strength lies in the quality of its services.

Metal Treating

      The market for metal-treating services is typically regional and
competitive. All regions in which the Company had facilities contained numerous
competitors. In addition, in-house heat-treating facilities provided a major
source of competition. The Company competed in this segment on the basis of
services provided, turnaround time, and price. The Company sold the businesses
comprising this segment in June 2000.

      (xi) Environmental Protection Regulations

      The Company believes that compliance by the Company with federal, state,
and local environmental protection regulations will not have a material adverse
effect on its capital expenditures, earnings, or competitive position.

      (xii)Number of Employees

      As of April 1, 2000, the Company employed approximately 2,700 persons.
Approximately 300 of these persons were employed by the BAC Killam and Metal
Treating businesses, which were sold subsequent to year-end.

                                       9
<PAGE>
</TABLE>
(d)   Financial Information About Geographic Areas

      The Company's sales in foreign locations are currently insignificant.

(e)   Executive Officers of the Registrant
<TABLE>
<CAPTION>
<S>     <C>                 <C>   <C>
        Name                Age   Present Title (Fiscal Year First Became Executive Officer)
        ------------------- ---   ---------------------------------------------------------

        Brian D. Holt        50   President and Chief Executive Officer (2001)
        Emil C. Herkert      62   Vice President (1996)
        Jeffrey L. Powell    41   Vice President (1994)
        Christine L. Leonard 35   Vice President, Finance and Administration (2001)
        Theo Melas-Kyriazi   40   Vice President and Chief Financial Officer
                                  (Principal Financial and Accounting Officer)
                                  (1999)

      Each executive officer serves until his successor is chosen or appointed
by the Board of Directors and qualified or until earlier resignation, death, or
removal. Mr. Holt was appointed President and Chief Executive Officer of the
Company in May 2000. Mr. Holt has been President and Chief Executive Officer of
Thermo Ecotek Corporation, another majority-owned subsidiary of Thermo Electron,
since February 1994 and is Chief Operating Officer, Energy and Environment, for
Thermo Electron, a position he has held since September 1998. Mr. Herkert has
served as President of Killam Associates, a subsidiary of Killam, since 1977 and
was appointed Chief Executive Officer of Randers Killam in May 1997. Mr. Powell
served as President of ThermoRetec and as its Chief Executive Officer from its
inception in 1993 and from May 1997, respectively, until April 1998, when he was
named Senior Vice President of ThermoRetec. Ms. Leonard has served as Controller
of the Company since August 1996 and was appointed Vice President, Finance and
Administration, in June 2000. Ms. Leonard was Controller of Thermo EuroTech from
July 1995 to August 1996. Mr. Melas-Kyriazi was appointed Chief Financial
Officer of the Company and Thermo Electron on January 1, 1999. He joined Thermo
Electron in 1986 as Assistant Treasurer, and became Treasurer in 1988. He was
named President and Chief Executive Officer of ThermoSpectra Corporation, a
subsidiary of Thermo Instrument Systems Inc., in 1994, a position he held until
becoming Vice President of Corporate Strategy for Thermo Electron in 1998. Mr.
Melas-Kyriazi remains a Vice President of Thermo Electron. Mr. Melas-Kyriazi is
a full-time employee of Thermo Electron, but devotes such time to the affairs of
the Company as the Company's needs reasonably require.

Item 2.  Properties

      The location and general character of the Company's principal properties
by segment as of April 1, 2000, are:

Environmental-liability Management

      The Company owns approximately 112,000 square feet of office, engineering,
laboratory, and production space, principally in Ireland, California, and the
Netherlands, and leases approximately 175,000 square feet of office,
engineering, laboratory, and production space pursuant to leases expiring in
fiscal 2001 through 2007, principally in Colorado, New Mexico, Pennsylvania,
Massachusetts, and Washington.

      The Company also owns approximately 78 acres in Maryland, California, and
Oregon, from which it provides soil-remediation services. The Company leases
approximately 2 acres in New York pursuant to a lease expiring in fiscal 2005
and 5 acres in Washington on a month-to-month basis, from which it provides
soil-remediation services.

      The Company leases approximately six acres in Arizona and one site in
Nevada, pursuant to leases expiring in fiscal 2003 and fiscal 2001,
respectively, upon which it has constructed fluids storage and processing
equipment.



                                       10
<PAGE>

      The Company occupies approximately 15 acres in Delfzijl, the Netherlands,
consisting of office space, distillation facilities, and oil storage tanks,
pursuant to a lease expiring in 2059. The lease is cancelable without penalty in
fiscal 2009.

Engineering and Design

      The Company owns approximately 65,000 square feet of office, engineering,
and laboratory space in New Jersey and Michigan, and leases approximately
160,000 square feet of office, engineering, and laboratory space pursuant to
leases expiring in fiscal 2001 through 2008, principally in Pennsylvania, New
Jersey, New Hampshire, Florida, and New York. Of these amounts, BAC Killam owned
approximately 9,000 square feet of office and engineering space in New Jersey
and leased approximately 26,000 square feet of office and engineering space,
primarily in New York. The Company sold the assets of BAC Killam on April 14,
2000.

Laboratory Testing

      The Company owns approximately 185,000 square feet of office and
laboratory space in Pennsylvania, and leases approximately 7,000 square feet of
office and laboratory space in Michigan pursuant to a lease expiring in fiscal
2001.

Metal Treating

      Prior to the June 2000 sale of the businesses comprising this segment, the
Company owned approximately 140,000 square feet of office, laboratory, and
production space in Minnesota and Wisconsin, and leased approximately 330,000
square feet of office, laboratory, and production space in California pursuant
to leases expiring in fiscal 2005.

      The Company believes that these facilities are in good condition and are
adequate for its present operations and that other suitable space is readily
available if any of such leases are not extended. With respect to leases
expiring in the near future, in the event the Company does not renew such
leases, the Company believes suitable alternate space is available for lease on
acceptable terms.

Item 3.  Legal Proceedings

      Not applicable.

Item 4.  Submission of Matters to a Vote of Security Holders

      Not applicable.


                                       11
<PAGE>

                                     PART II

Item 5.  Market for Registrant's Common Equity and Related Stockholder Matters

      Information concerning the market and market price for the Registrant's
Common Stock, $.10 par value, and dividend policy are included under the
sections labeled "Common Stock Market Information" and "Dividend Policy" in the
Registrant's Fiscal 2000 Annual Report to Shareholders and is incorporated
herein by reference.

Item 6.  Selected Financial Data

      The information required under this item is included under the sections
labeled "Selected Financial Information" and "Dividend Policy" in the
Registrant's Fiscal 2000 Annual Report to Shareholders and is incorporated
herein by reference.

Item 7.  Management's Discussion and Analysis of Financial Condition and Results of Operations

      The information required under this item is included under the heading
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" in the Registrant's Fiscal 2000 Annual Report to Shareholders and is
incorporated herein by reference.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

      The information required under this item is included under the heading
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" in the Registrant's Fiscal 2000 Annual Report to Shareholders and is
incorporated herein by reference.

Item 8.  Financial Statements and Supplementary Data

      The Registrant's Consolidated Financial Statements as of April 1, 2000,
are included in the Registrant's Fiscal 2000 Annual Report to Shareholders and
are incorporated herein by reference.

Item 9.  Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

      Not applicable.

                                    PART III

      The information required by Items 10, 11, 12, and 13 of Form 10-K will be
filed as part of an amendment to this Form 10-K no later than 120 days after
April 1, 2000, the end of the Registrant's fiscal year covered by this Form
10-K.


                                       12
<PAGE>

                                     PART IV
Item 14.  Exhibits, Financial Statement Schedules, and Reports on Form 8-K

(a,d)  Financial Statements and Schedules

       (1)The consolidated financial statements set forth in the list below are
          filed as part of this Report.

       (2)The consolidated financial statement schedule set forth in the list
          below is filed as part of this Report.

       (3)Exhibits filed herewith or incorporated herein by reference are set
          forth in Item 14(c) below.

       List of Financial Statements and Schedules Referenced in this Item 14

       Information incorporated by reference from Exhibit 13 filed herewith:

          Consolidated Statement of Operations
          Consolidated Balance Sheet
          Consolidated Statement of Cash Flows
          Consolidated Statement of Comprehensive Income and Shareholders' Investment
          Notes to Consolidated Financial Statements
          Report of Independent Public Accountants

       Financial Statement Schedule filed herewith:

          Schedule II:  Valuation and Qualifying Accounts

       All other schedules are omitted because they are not applicable or not
       required, or because the required information is shown either in the
       financial statements or the notes thereto.

(b)    Reports on Form 8-K

       On February 11, 2000, the Company filed a Current Report on Form 8-K
       dated as of January 28, 2000, with respect to the sale of the Randers
       division of The Randers Killam Group Inc., a subsidiary of the Company.

       On March 21, 2000, the Company filed a Current Report on Form 8-K dated
       as of March 6, 2000, with respect to the sale of a soil-remediation
       facility by ThermoRetec Corporation, a subsidiary of the Company.

(c)    Exhibits

       See Exhibit Index on the page immediately preceding exhibits.


                                       13
<PAGE>

                                   SIGNATURES

      Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed by
the undersigned, thereunto duly authorized.

Date:  June 23, 2000                  THERMO TERRATECH INC.


                                      By: /s/ Brian D. Holt
                                          Brian D. Holt
                                          President and Chief Executive Officer

      Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
Registrant and in the capacities indicated, as of June 23, 2000.

Signature                             Title


By:  /s/ Brian D. Holt                President, Chief Executive Officer, and Director
     Brian D. Holt


By:  /s/ Theo Melas-Kyriazi           Vice President and Chief Financial Officer
     Theo Melas-Kyriazi               (Principal Financial and Accounting Officer)


By:  /s/ John P. Appleton             Chairman of the Board and Director
     John P. Appleton


By:  /s/ Donald E. Noble              Director
     Donald E. Noble


By:  /s/ William A. Rainville         Director
     William A. Rainville


By:  /s/ Polyvios C. Vintiadis        Director
     Polyvios C. Vintiadis


                                       14
<PAGE>

                    Report of Independent Public Accountants

To the Shareholders and Board of Directors of Thermo TerraTech Inc.:

      We have audited, in accordance with generally accepted auditing standards,
the consolidated financial statements included in Thermo TerraTech Inc.'s Annual
Report to Shareholders incorporated by reference in this Form 10-K, and have
issued our report thereon dated May 18, 2000 (except with respect to the matters
discussed in Note 17, as to which the date is June 1, 2000). Our audits were
made for the purpose of forming an opinion on those statements taken as a whole.
The schedule listed in Item 14 on page 13 is the responsibility of the Company's
management and is presented for purposes of complying with the Securities and
Exchange Commission's rules and is not part of the basic consolidated financial
statements. This schedule has been subjected to the auditing procedures applied
in the audits of the basic consolidated financial statements and, in our
opinion, fairly states in all material respects the consolidated financial data
required to be set forth therein in relation to the basic consolidated financial
statements taken as a whole.



                                                          Arthur Andersen LLP



Boston, Massachusetts
May 18, 2000


                                       15
<PAGE>
</TABLE>

SCHEDULE II

                              THERMO TERRATECH INC.
                        Valuation and Qualifying Accounts
                                 (In thousands)
<TABLE>
<CAPTION>
<S>                                 <C>         <C>          <C>          <C>        <C>          <C>
 Description                                     Provision    Accounts    Accounts   Other (a)    Balance
                                    Balance at  Charged to   Recovered     Written                 at End
                                     Beginning     Expense                     Off                of Year
                                       of Year
----------------------------------- ----------- ----------- ----------- ----------- ----------- ----------

Allowance for Doubtful Accounts

Year Ended April 1, 2000               $ 3,577     $   715     $  (674)    $(1,110)    $   187     $ 2,695

Year Ended April 3, 1999               $ 4,450     $ 2,085     $   (45)    $(2,479)    $  (434)    $ 3,577

Year Ended April 4, 1998               $ 3,838     $ 1,141     $     -     $  (773)    $   244     $ 4,450


</TABLE>
<TABLE>
<CAPTION>
<S>                                     <C>           <C>             <C>          <C>            <C>
 Description                            Balance at      Provision         Cash     Other (d)      Balance
                                         Beginning     Charged to     Payments                     at End
                                           of Year    Expense (c)                                 of Year
------------------------------------- ------------- -------------- ------------ ------------- ------------

Accrued Restructuring Costs (b)

Year Ended April 1, 2000                    $1,719       $ 6,219        $ (895)     $ (1,136)      $5,907

Year Ended April 3, 1999                    $    -       $ 2,095        $ (376)     $      -       $1,719


(a) Includes allowances of businesses acquired during the year as described in
    Note 2 to Consolidated Financial Statements in the Registrant's Fiscal 2000
    Annual Report to Shareholders. The fiscal 1999 amount includes an acquired
    company's reserves that were not required and were therefore reversed to
    cost in excess of net assets of acquired companies.
(b) The nature of activity in this account is described in Note 11 to
    Consolidated Financial Statements in the Registrant's Fiscal 2000 Annual
    Report to Shareholders.
(c) Excludes provision of $50.8 million in fiscal 2000, primarily for
    write-downs of cost in excess of net assets of acquired companies and fixed
    assets, and $8.1 million in fiscal 1999, for fixed asset and intangible
    asset write-downs.
(d) Includes reserves reversed due to sale of businesses and the effect of currency translation.


                                       16
<PAGE>

                                  EXHIBIT INDEX
Exhibit
Number         Description of Exhibit

 2.1           Purchase and Sale Agreement executed October 6, 1997, by and
               among Remediation Technologies, Inc., RETEC Thermal, Inc., TETRA
               Thermal, Inc., and TETRA Technologies, Inc. (filed as Exhibit 2.1
               to Thermo Remediation Inc.'s Current Report on Form 8-K dated
               October 6, 1997 [File No. 1-12636] and incorporated herein by
               reference).

 2.2           Assignment and Assumption Agreement executed October 6, 1997, by
               and among Remediation Technologies, Inc., RETEC Thermal, Inc.,
               TETRA Thermal, Inc., and TETRA Technologies, Inc. (filed as
               Exhibit 2.2 to Thermo Remediation Inc.'s Current Report on Form
               8-K dated October 6, 1997 [File No. 1-12636] and incorporated
               herein by reference).

 2.3           Asset Purchase Agreement dated as of October 10, 1997, between the Registrant and
               Holcroft L.L.C. (filed as Exhibit 2.1 to the Registrant's Current Report on Form 8-K
               dated October 10, 1997 [File No. 1-9549] and incorporated herein by reference).

 2.4           $2,218,000.00 Principal Promissory Note issued by Holcroft L.L.C. to the Registrant
               (filed as Exhibit 2.2 to the Registrant's Current Report on Form 8-K dated October 10,
               1997 [File No. 1-9549] and incorporated herein by reference).

 2.5           $663,117.82 Principal Promissory Note issued by Holcroft L.L.C. to the Registrant (filed
               as Exhibit 2.3 to the Registrant's Current Report on Form 8-K dated October 10, 1997
               [File No. 1-9549] and incorporated herein by reference).

 2.6           Subordination Agreement dated as of October 10, 1997, between the
               Registrant and Comerica Bank (filed as Exhibit 2.4 to the
               Registrant's Current Report on Form 8-K dated October 10, 1997
               [File No. 1-9549] and incorporated herein by reference).

 2.7           Stock Purchase and Sale Agreement dated May 12, 1997, by and
               between the Registrant and Thomas R. Eurich, Michael J.
               Krivitzky, Thomas J. McEnhill, and Bruce M. Bourdon (filed as
               Exhibit (iv) to Amendment No. 3 to Schedule 13D filed by Thermo
               Electron Corporation, Thermo Power Corporation, and the
               Registrant on May 13, 1997, and incorporated herein by
               reference).

 2.8           Amendment No. 1 dated September 19, 1997, to Stock Purchase and
               Sale Agreement dated May 12, 1997, by and between the Registrant
               and Thomas R. Eurich, Michael J. Krivitzky, Thomas J. McEnhill,
               and Bruce M. Bourdon (filed as Exhibit 2.5 to The Randers Group
               Incorporated's Annual Report on Form 10-K for the fiscal year
               ended April 4, 1998 [File No. 0-18095] and incorporated herein by
               reference).

 2.9           Reserved.

2.10           Stock Purchase Agreement entered on September 19, 1997, by and between
               the Registrant and The Randers Group Incorporated (filed as
               Exhibit (vii) to Amendment No. 4 to Schedule 13D filed by Thermo
               Electron Corporation and the Registrant on October 3, 1997, and
               incorporated herein by reference).

2.11           Amendment No. 1 dated as of April 4, 1998, to Stock Purchase
               Agreement entered on September 19, 1997, by and between the
               Registrant and The Randers Group Incorporated (filed as Exhibit
               2.8 to The Randers Killam Group Incorporated's Annual Report on
               Form 10-K for the fiscal year ended April 4, 1998 [File No.
               0-18095] and incorporated herein by reference).



                                       17
<PAGE>

Exhibit
Number         Description of Exhibit

2.12           Agreement by and among the Registrant, The Randers Group
               Incorporated, Thomas R. Eurich, Michael J. Krivitzky, Thomas J.
               McEnhill, Bruce M. Bourdon, and David A. Wiegerink (filed as
               Exhibit 10 to The Randers Group Incorporated's Current Report on
               Form 8-K dated October 3, 1997 [File No. 0-18095] and
               incorporated herein by reference).

2.13           Agreement and Plan of Merger dated as of October 19, 1999, by and
               among Thermo Electron Corporation, TTT Acquisition Corporation,
               and the Registrant (filed as Exhibit 2.1 to the Registrant's
               Current Report on Form 8-K relating to events occurring on
               October 19, 1999 [File No. 1-9549] and incorporated herein by
               reference).

2.14           Asset Purchase Agreement by and among RGI Muskegon, Inc. (as
               Buyer), Randers Engineering, Inc., Redeco, Inc., Viridian
               Technology, Inc., and Randers Group Property Corporation (as
               Sellers), and The Randers Killam Group Inc. (as Seller's Parent)
               dated January 28, 2000 (filed as Exhibit 2.1 to The Randers
               Killam Group Inc.'s Current Report on Form 8-K dated as of
               January 28, 2000 [File No. 0-18095] and incorporated herein by
               reference).

2.15           Amendment No. 1 to Agreement and Plan of Merger dated as of April 12, 2000, by and among
               Thermo Electron Corporation, TTT Acquisition Corporation, and the Registrant (filed as
               Appendix A-1 to Thermo Electron Corporation's Amendment No. 2 to its Registration
               Statement on Form S-4 [Reg. No. 333-90661] and incorporated herein by reference).

2.16           Asset Purchase Agreement dated March 6, 2000, by and among TPST
               Soil Recyclers of California, Inc. and Nove Investments I, LLC
               (filed as Exhibit 2.1 to ThermoRetec Corporation's Form 8-K dated
               as of March 21, 2000 [File No. 1-12636] and incorporated herein
               by reference).

2.17           Asset Purchase Agreement by and among BAC Killam, Inc. and The Randers Killam Group Inc.
               (as Sellers) and Hatch Mott McDonald, Inc. (as Buyer), dated as of March 31, 2000 (filed
               as Exhibit 2.1 to The Randers Killam Group Inc.'s Form 8-K dated as of April 14, 2000
               [File No. 0-18095] and incorporated herein by reference).

2.18           Asset Purchase Agreement by and among the Registrant,
               Metallurgical, Inc., Cal-Doran Metallurgical Services, Inc., and
               Metal Treating Inc. (as Sellers) and Lindberg Corporation (as
               Buyer), dated as of May 31, 2000 (filed as Exhibit 2.1 to the
               Registrant's Current Report on Form 8-K dated as of June 1, 2000
               [File No. 1-9549] and incorporated herein by reference).

 3.1           Restated Certificate of Incorporation, as amended (filed as Exhibit 99 to the
               Registrant's Registration Statement on Form S-2 [Reg. No. 333-02269] and incorporated
               herein by reference).

 3.2           Bylaws of the Registrant (filed as Exhibit 3(b) to the Registrant's Annual Report on Form
               10-K for the fiscal year ended April 2, 1988 [File No. 1-9549] and incorporated herein by
               reference).

 4.1           Fiscal Agency Agreement dated as of May 2, 1996, among the
               Registrant, Thermo Electron Corporation, and Chemical Bank, as
               Fiscal Agent (filed as Exhibit 4.2 to the Registrant's Annual
               Report on Form 10-K for the fiscal year ended March 30, 1996
               [File No. 1-9549] and incorporated herein by reference).

               The Registrant hereby agrees, pursuant to Item 601(b)(4)(iii) (A)
               of Regulation S-K, to furnish to the Commission, upon request, a
               copy of each other instrument with respect to other long-term
               debt of the Company or its subsidiaries.


                                       18
<PAGE>

Exhibit
Number         Description of Exhibit

10.1           Thermo Electron Corporate Charter as amended and restated
               effective January 3, 1993 (filed as Exhibit 10(a) to the
               Registrant's Annual Report on Form 10-K for the fiscal year ended
               April 3, 1993 [File No. 1-9549] and incorporated herein by
               reference).

10.2           Amended and Restated Corporate Services Agreement dated January 3, 1993, between Thermo
               Electron Corporation and the Registrant (filed as Exhibit 10(b) to the Registrant's
               Annual Report on Form 10-K for the fiscal year ended April 3, 1993 [File No. 1-9549] and
               incorporated herein by reference).

10.3           Agreement of Lease dated December 31, 1985, between Claridge Properties Ltd. and Thermo
               Electron Corporation (filed as Exhibit 10(c) to the Registrant's Registration Statement
               on Form S-1 [Reg. No. 33-6763] and incorporated herein by reference).

10.4           Assignment of Lease dated December 31, 1985, between Thermo
               Electron Corporation and TMO, Inc. (filed as Exhibit 10(d) to the
               Registrant's Registration Statement on Form S-1 [Reg.
               No. 33-6763] and incorporated herein by reference).

10.5           Sublease dated March 30, 1986, between TMO, Inc. and  Holcroft/Loftus, Inc. (filed as
               Exhibit 10(e) to the Registrant's Registration Statement on Form S-1 [Reg. No. 33-6763]
               and incorporated herein by reference).

10.6           Lease Amending Agreement dated January 1, 1995, between Claridge
               Properties Ltd., Thermo Electron Corporation, and TMO, Inc.
               (filed as Exhibit 10.6 to the Registrant's Annual Report on Form
               10-K for the fiscal year ended April 1, 1995 [File No. 1-9549]
               and incorporated by reference).

10.7           Second Amendment to Sublease dated as of October 10,  1997, between the Registrant and
               TMO, Inc. (filed as Exhibit 2.5 to the Registrant's Current Report on Form 8-K dated
               October 10, 1997 [File No. 1-9549] and incorporated herein by reference).

10.8           Sublease dated as of October 10, 1997, between the Registrant and Holcroft L.L.C. (filed
               as Exhibit 2.6 to the Registrant's Current Report on Form 8-K dated October 10, 1997
               [File No. 1-9549] and incorporated herein by reference).

10.9           Exclusive License and Marketing Agreement dated March 22, 1990,
               among TPS Technologies Inc., Holcroft Inc., and Thermo Soil
               Recyclers Inc. (filed as Exhibit 10(q) to the Registrant's Annual
               Report on Form 10-K for the fiscal year ended March 31, 1990
               [File No. 1-9549] and incorporated herein by reference).

10.10          Form of Indemnification Agreement with Directors and Officers (filed as Exhibit 10(k) to
               the Registrant's Annual Report on Form 10-K for the fiscal year ended March 30, 1991
               [File No. 1-9549] and incorporated herein by reference).

10.11          Development Agreement dated September 15, 1991, between Thermo
               Electron Corporation and the Registrant (filed as Exhibit 10(l)
               to the Registrant's Quarterly Report on Form 10-Q for the fiscal
               quarter ended September 28, 1991 [File No. 1-9549] and
               incorporated herein by reference).


                                       19
<PAGE>

Exhibit
Number         Description of Exhibit

10.12          Amended and Restated Development Agreement dated January 2, 1992, between Thermo Electron
               Corporation and the Registrant (filed as Exhibit 10(m) to the Registrant's Annual Report
               on Form 10-K for the fiscal year ended March 28, 1992 [File No. 1-9549] and incorporated
               herein by reference).

10.13          Asset Transfer Agreement dated as of October 1, 1993, among the Registrant, TPS
               Technologies Inc., and Thermo Remediation Inc. (filed as Exhibit 2.3 to Thermo
               Remediation Inc.'s Registration Statement on Form S-1 [Reg. No. 33-70544] and
               incorporated herein by reference).

10.14          Exclusive License Agreement dated as of October 1, 1993, among the Registrant, TPS
               Technologies Inc., and Thermo Remediation Inc. (filed as Exhibit 2.4 to Thermo
               Remediation Inc.'s Registration Statement on Form S-1 [Reg. No. 33-70544] and
               incorporated herein by reference).

10.15          Non-Competition and Non-Disclosure Agreement dated as of October 1, 1993, among the
               Registrant, TPS Technologies Inc., and Thermo Remediation Inc. (filed as Exhibit 2.5 to
               Thermo Remediation Inc.'s Registration Statement on Form S-1 [Reg. No. 33-70544] and
               incorporated herein by reference).

10.16          Tax Allocation Agreement dated as of June 1, 1992, between the Registrant and Thermo
               Remediation Inc. (filed as Exhibit 10.3 to Thermo Remediation Inc.'s Registration
               Statement on Form S-1 [Reg. No. 33-70544] and incorporated herein by reference).

10.17          Agreement of Partnership dated May 16, 1994, among Terra Tech
               Labs Inc. (a wholly owned subsidiary of the Registrant) and
               Eberline Analytical Corporation, Skinner & Sherman, Inc.,
               TMA/NORCAL Inc., Normandeau Associates Inc., Bettigole Andrews &
               Clark Inc., Fellows, Read & Associates Inc., and Thermo
               Consulting Engineers Inc. (each a wholly owned subsidiary of
               Thermo Instrument Systems Inc.; filed as Exhibit 1 to the
               Registrant's Current Report on Form 8-K relating to the events
               occurring on May 16, 1994 [File No. 1-9549] and incorporated
               herein by reference).

10.18          Promissory Note dated May 16, 1994, issued by the Registrant to
               Thermo Electron Corporation (filed as Exhibit 2 to the
               Registrant's Current Report on Form 8-K relating to the events
               occurring on May 16, 1994 [File No. 1-9549] and incorporated
               herein by reference).

10.19          Agreement of Dissolution of Partnership dated May 9, 1995, among
               Thermo Terra Tech (the Partnership), Terra Tech Labs, Inc. (a
               wholly owned subsidiary of the Registrant) and Eberline
               Analytical Corporation, Skinner & Sherman, Inc., TMA/NORCAL Inc.,
               Normandeau Associates Inc., Bettigole Andrews & Clark Inc.,
               Fellows, Read & Associates Inc., and Thermo Consulting Engineers
               Inc. (each a wholly owned subsidiary of Thermo Instrument Systems
               Inc.; filed as Exhibit 2.1 to the Registrant's Current Report on
               Form 8-K relating to the events occurring on May 9, 1995 [File
               No. 1-9549] and incorporated herein by reference).

10.20          Stock Purchase Agreement dated May 9, 1995, between the
               Registrant and Thermo Instrument Systems Inc. (filed as Exhibit
               2.2 to the Registrant's Current Report on Form 8-K relating to
               the events occurring on May 9, 1995 [File No. 1-9549] and
               incorporated herein by reference).

10.21          Note dated May 17, 1995, from the Registrant to Thermo Electron Corporation (filed as
               Exhibit 2.3 to the Registrant's Current Report on Form 8-K relating to the events
               occurring on May 9, 1995 [File No. 1-9549] and incorporated herein by reference).


                                       20
<PAGE>

Exhibit
Number         Description of Exhibit

10.22          Stock Purchase and Note Issuance Agreement dated as of November 22, 1993, between the
               Registrant and Thermo Remediation Inc. (filed as Exhibit 10.11 to Thermo Remediation
               Inc.'s Registration Statement on Form S-1 [Reg. No. 33-70544] and incorporated herein by
               reference).

10.23          $2,650,000 principal amount Subordinated Convertible Note dated
               as of November 22, 1993, made by Thermo Remediation Inc., issued
               to the Registrant (filed as Exhibit 10.12 to Thermo Remediation
               Inc.'s Registration Statement on Form S-1 [Reg. No. 33-70544] and
               incorporated herein by reference).

10.24          Stock Purchase and Sale Agreement made and entered into on February 6, 1995, to be
               effective as of January 29, 1995, by and between Nord Est S.A., the Registrant, and Emil
               C. Herkert, Kenneth L. Zippler, Franklin O. Williamson, Jr., Fletcher N. Platt, Jr.,
               Eugene J. Destefano, Meint Olthof, and Stanley P. Kaltnecker, Jr. (filed as Exhibit 1 to
               the Registrant's Current Report on Form 8-K relating to the events occurring on February
               6, 1995 [File No. 1-9549] and incorporated herein by reference).

10.25          Agreement and Plan of Merger dated as of June 28, 1995, by and
               among the Registrant, Eberline Acquisition Inc., Thermo
               Remediation Inc., and Eberline Holdings Inc. (filed as Appendix B
               to Thermo Remediation Inc.'s Proxy Statement for the Annual
               Meeting held on December 13, 1995 [File No. 1-12636] and
               incorporated herein by reference).

10.26          $28,000,000 Secured Promissory Note dated as of January 29, 1995,
               issued by the Registrant to Nord Est S.A. (filed as Exhibit 2 to
               the Registrant's Current Report on Form 8-K relating to the
               events occurring on February 6, 1995 [File No. 1-9549] and
               incorporated herein by reference).

10.27          $38,000,000 Promissory Note dated as of February 21, 1995, issued
               by the Registrant to Thermo Electron Corporation (filed as
               Exhibit 3 to the Registrant's Current Report on Form 8-K relating
               to the events occurring on February 6, 1995 [File No. 1-9549] and
               incorporated herein by reference).

10.28          Asset Purchase Agreement by and among Thermo Analytical Inc. (as Buyer); Lancaster
               Laboratories, Inc. and Clewmark Holdings (as Sellers); and Earl H. Hess, Anita F. Hess,
               Kenneth E. Hess, J. Wilson Hershey, and Carol D. Hess (as the principal owners of
               Sellers) (filed as Exhibit 1 to the Registrant's Current Report on Form 8-K relating to
               the events occurring on May 10, 1995 [File No. 1-9549] and incorporated herein by
               reference).

10.29          Agreement and Plan of Merger dated as of the first day of
               December 1995, by and among Thermo Remediation Inc., TRI
               Acquisition Inc., and Remediation Technologies, Inc. (filed as
               Exhibit 2(a) to the Registrant's Current Report on Form 8-K
               relating to the events occurring on December 8, 1995 [File No.
               1-9549] and incorporated herein by reference).

10.30          Purchase and Sale Agreement dated as of December 20, 1994, by and
               among TPS Technologies Inc., TPST Soil Recyclers of Maryland
               Inc., Rafich Corporation, Harry Ratrie, John C. Cyphers, and J.
               Thomas Hood (filed as Exhibit 1 to Thermo Remediation Inc.'s
               Current Report on Form 8-K for the events occurring on December
               21, 1994 [File No. 1-12636] and incorporated herein by
               reference).

10.31          Stock Purchase Agreement entered into on March 29, 1995, by and
               among Stalt Holding, B.V., Beheersmaatschappij J. Amerika N.V.,
               A.J. Van Es, J.B. Van Es and D.A. Slager, and the Registrant
               (filed as Exhibit 1 to the Registrant's Current Report on Form
               8-K relating to the events occurring on March 29, 1995 [File No.
               1-9549] and incorporated herein by reference).



                                       21
<PAGE>

Exhibit
Number         Description of Exhibit

10.32          Amended and Restated Thermo TerraTech Inc. - The Randers Group
               Incorporated Nonqualified Stock Option Plan.

10.33          Incentive Stock Option Plan of the Registrant (filed as Exhibit
               10(h) to the Registrant's Registration Statement on Form S-1
               [Reg. No. 33-6763] and incorporated herein by reference).
               (Maximum number of shares issuable in the aggregate under this
               plan and the Registrant's Nonqualified Stock Option Plan is
               1,850,000 shares, after adjustment to reflect share increases
               approved in 1987, 1989, and 1992, 6-for-5 stock splits effected
               in July 1988 and March 1989, and 3-for-2 stock split effected in
               September 1989.)

10.34          Amended and Restated Nonqualified Stock Option Plan of the
               Registrant. (Maximum number of shares issuable in the aggregate
               under this plan and the Registrant's Incentive Stock Option Plan
               is 1,850,000 shares, after adjustment to reflect share increases
               approved in 1987, 1989, and 1992, 6-for-5 stock splits effected
               in July 1988 and March 1989, and 3-for-2 stock split effected in
               September 1989.)

10.35          Amended and Restated Deferred Compensation Plan for Directors of
               the Registrant.

10.36          Amended and Restated Equity Incentive Plan.

10.37          Amended and Restated Directors Stock Option Plan.

10.38          Amended and Restated Thermo TerraTech Inc. (formerly Thermo
               Process Systems Inc.) - Thermo Remediation Inc. Nonqualified
               Stock Option Plan.

               In addition to the stock-based compensation plans of the
               Registrant, the executive officers of the Registrant may be
               granted awards under stock-based compensation plans of Thermo
               Electron for services rendered to the Registrant or to such
               affiliated corporations. The terms of such plans are
               substantially the same as those of the Registrant's Equity
               Incentive Plan.

10.39          Restated Stock Holdings Assistance Plan and Form of Executive Loan (filed
               as Exhibit 10.42 to the Registrant's Annual Report on Form 10-K
               for the fiscal year ended March 29, 1997 [File No. 1-9549] and
               incorporated herein by reference).

10.40          Deferred Compensation Agreement dated September 16, 1996, between Elson T.
               Killam Associates Inc. and Emil C. Herkert (filed as Exhibit 10.1
               to the Registrant's Quarterly Report on Form 10-Q for the fiscal
               quarter ended July 4, 1998 [File No. 1-9549] and incorporated
               herein by reference).

10.41          Addendum dated 1990, to Deferred Compensation Agreement dated September
               16, 1986, between Elson T. Killam Associates Inc. and Emil C.
               Herkert (filed as Exhibit 10.2 to the Registrant's Quarterly
               Report on Form 10-Q for the fiscal quarter ended July 4, 1998
               [File No. 1-9549] and incorporated herein by reference).

10.42          Amendment No. 1, dated April 27, 1990, to Deferred Compensation Agreement dated September 16, 1986,
               between Elson T. Killam Associates Inc. and Emil C. Herkert (filed as Exhibit 10.3 to the
               Registrant's Quarterly Report on Form 10-Q for the fiscal quarter ended July 4, 1998
               [File No. 1-9549] and incorporated herein by reference).


                                       22
<PAGE>

Exhibit
Number         Description of Exhibit

10.43          Master Cash Management, Guarantee Reimbursement, and Loan Agreement
               dated as of June 1, 1999, between the Registrant and Thermo
               Electron Corporation (filed as Exhibit 10.43 to the Registrant's
               Annual Report on Form 10-K for the fiscal year ended April 3,
               1999 [File No. 1-9549] and incorporated herein by reference).

10.44          Master Cash Management, Guarantee Reimbursement, and Loan Agreement
               dated as of June 1, 1999, between ThermoRetec Corporation and
               Thermo Electron Corporation (filed as Exhibit 10.17 to
               ThermoRetec Corporation's Annual Report on Form 10-K for the
               fiscal year ended April 3, 1999 [File No. 1-12636] and
               incorporated herein by reference).

10.45          Master Cash Management, Guarantee Reimbursement, and Loan Agreement
               dated as of June 1, 1999, between The Randers Killam Group Inc.
               and Thermo Electron Corporation (filed as Exhibit 10.18 to The
               Randers Killam Group Inc.'s Annual Report on Form 10-K for the
               fiscal year ended April 3, 1999 [File No. 0-18095] and
               incorporated herein by reference).

10.46          Retention Agreement dated as of November 17, 1999, between Thermo
               Electron Corporation and John P. Appleton.

10.47          Retention Agreement between the Registrant and Emil C. Herkert.

10.48          Retention Agreement between the Registrant and Jeffrey L. Powell.

  13           Annual Report to Shareholders for the fiscal year ended April 1,
               2000 (only those portions incorporated herein by reference).

  21           Subsidiaries of the Registrant.

  23           Consent of Arthur Andersen LLP.

  27           Financial Data Schedule.
</TABLE>