Exhibit 8.1
 
                       [SHAFFER & ASSOCIATES LETTERHEAD]
 
                                                                 August 25, 1998
 
Dectron Internationale Inc.
4300 Poirier Blvd.
Montreal, Quebec H4R 2C5
Canada
 
Gentlemen:
 
    You have requested our opinion as to certain Canadian federal income tax
considerations for persons not residents in Canada.
 
    In the opinion of Shaffer & Associates, special Canadian counsel to the
Company, the following are the principal Canadian federal income tax
considerations under the Income Tax Act (Canada) and the regulations thereunder
(collectively, the "Canadian Act'), the administrative practices of Revenue
Canada, Customs, Excise & Taxation and proposed amendments to the Canadian Act
and the regulations thereunder publicly announced by the Minister of Finance
prior to the date hereof generally applicable to acquiring, holding and
disposing of Common Stock and Warrants. There is no assurance that any proposed
amendments tot he Tax Act or the regulations thereunder will be enacted as
proposed, if at all. It is assumed that at all material times the Common Stock
and Warrants will be listed on NASDAQ, or some other Canadian or foreign stock
exchange. Currently, neither NASDAQ nor any other foreign stock exchange is
prescribed for the purpose of section 115 of the Canadian Act. Proposals in
former Bill C-69 which if enacted will have effect from April 29, 1995 will
prescribe NASDAQ and certain other foreign stock exchanges for the purposes of
section 115 of the Canadian Act. Comment is restricted to prospective investors
(each an "Investor") who for the purposes of the Canadian Act are not resident
in Canada, hold all such Common Stock and Warrants and will hold all Common
Stock acquired on exercise thereof, solely as capital property, who deal at
arm's length with the Company and whose warrants and Common Stock will not at
any material time constitute 'taxable Canadian property' for the purpose of the
Canadian Act. Generally, neither a share of Common Stock, nor a Warrant will
constitute "taxable Canadian property" of an Investor provided, among other
things, that the Company is a public company in that at least one class of its
shares are listed on a prescribed stock exchange in Canada. However, the
Ministry of Finance proposes that after April 26, 1995 shares listed on certain
U.S. stock exchanges, including NASDAQ, will not be 'taxable Canadian property"
provided either that the Investor did not hold such security as capita property
used in carrying on a business in Canada, or that neither the Investor nor
persons with whom the Investor did not deal at arm's length alone or together
owned 25% or more of the issued shares of any class of the Company at any time
in the five years immediately proceeding a disposition of the Common Stock or
Warrants. For these purposes, a right or option to acquire a share, including on
exercise of a Warrant, is considered to be equivalent to a share.
 
    This opinion does not take into account any provincial or foreign income tax
legislation or considerations nor does it take into account or anticipate any
changes in law or administrative practice including by way of judicial decision
or legislative action.
 
    This opinion is of a general nature and is not, and should not be construed
as, advice to any particular Investor as to Canadian Tax consequences applicable
to the Investor. Each Investor is urged to consult with the Investor's legal
professional advisors regarding tax and other legal consequences applicable to
the Investor's particular circumstances.
 
EXERCISE OF WARRANT
 
    An Investor will not incur liability for Canadian tax upon exercise of a
Warrant. The cost of the Investor of Common Stock acquired on exercise of a
Warrant will equal the adjusted cost base of the Warrant so exercised, plus any
amount paid by the Investor to exercise the Warrant.

DIVIDENDS ON COMMON STOCK
 
    An Investor will be liable to pay Canadian withholding tax equal to 25% (or
such lesser rate as may be provided under an applicable tax treaty) of the gross
amount of any dividend actually or deemed to have been paid or credited to the
Investor on the Investor's Common Stock. An Investor who is a resident of the
United States for purposes of the Canada-U.S. Income Tax Convention is subject
to a lesser tax of 15% of the gross amount of any dividend actually or deemed to
have been paid or credited to the Investor on the investor's Common Stock if the
Investor holds less than 10% of the voting stock of the Company, or 5% if the
Investor holds 10% or more of the voting stock of the Company, The Company will
be required to withhold the tax from the gross amount of the dividend, and to
remit the tax to the Receiver General of Canada for the account of the Investor.
Investors who are entitled to reduced withholding tax under an applicable treaty
must provide appropriate evidence of that entitlement satisfactory tot he
Company.
 
DISPOSING OF COMMON STOCK
 
    An Investor will not incur liability for Canadian tax upon disposing of
Common Stock except where the Common Stock is redeemed or repurchased by the
Company, in which case a dividend could be deemed to result (see Dividends on
Common Stock above).
 
    We consent to the use of our name and opinion in connection with references
to Canadian laws, regulations, treaties and potential liabilities in Dectron
Internationale Inc.'s Registration Statement. We note that our name is
specifically referred to in the Registration Statement under the heading "Civil
Liabilities" and in connection with the information contained under the heading
"Tax Aspects of the Offering" and confirm that we are giving our opinion with
respect to the information indicated therein.
 

                               
                                Very truly yours,
 
                                SHAFFER & ASSOCIATES
 
                                By:           /s/ SHAFFER & ASSOCIATES
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