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                                                                     Exhibit 5.1

               [RUBIN BAUM LEVIN CONSTANT & FRIEDMAN LETTERHEAD]


                                  May 14, 1998



Trans-Resources, Inc.
9 West 57th Street
New York, New York  10019

         Re:      10 3/4% Senior Notes due 2002, Series B and 12% Senior
                  Discount Notes due 2008, Series B (collectively, the "New
                  Notes")

Gentlemen:

         We have acted as counsel to Trans-Resources, Inc. (the "Company") in
connection with the Company's exchange offer (the "Exchange Offer") for its 10
3/4% Senior Notes due 2008, Series A and 12% Senior Discount Notes, due 2008,
Series A (collectively the "Old Notes") as described in the Prospectus (the
"Prospectus") contained in Amendment No. 1 to the Registration Statement on Form
S-4, Registration No. 333-51729 (the "Registration Statement"), to be filed with
the Securities and Exchange Commission.

         In furnishing this opinion, we have examined the Certificate of
Incorporation and By-laws of the Company, as amended, as well as the originals
or photostatic or certified copies of such documents, records, certificates,
agreements and other papers as we have deemed necessary for the purposes of this
opinion. In such examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals, the conformity
to executed documents of all unexecuted copies submitted to us, and the
authenticity of, and the conformity to, original documents of all documents
submitted to us as certified or photostatic copies. As to various questions of
fact material to our opinion, we have relied upon oral statements, written
information and certificates of officials and representatives of the Company and
others.
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Trans-Resources, Inc.
May 14, 1998
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         Based upon the foregoing, we are of the opinion that the New Notes to
be offered and issued by the Company have been duly authorized and, when
executed and authenticated in accordance with the terms of the Indentures
pursuant to which they will be issued and delivered in exchange for the
applicable Old Notes in accordance with the Exchange Offer will be validly
issued and constitute binding obligations of the Company, except as the
enforceability thereof may be limited by bankruptcy, insolvency, reorganization
or similar laws affecting creditors' rights generally or by general equitable
principles.

         As members of the Bar of the State of New York, we do not purport to be
experts on any laws other than those of the United States and New York, and the
General Corporation Law of Delaware.

         We consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference made to this firm under the caption
"Legal Matters" in the Prospectus. In giving this consent, we do not thereby
admit that we are included within the category of persons whose consent is
required under Section 7 of the Securities Act of 1933 or the rules and
regulations of the Securities and Exchange Commission promulgated thereunder.

         This opinion is rendered solely to you in connection with the above
matter. This opinion may not be relied upon by you for any other purpose or
relied upon by or furnished to any other person without our prior written
consent.

                                       Very truly yours,

                                       /s/ Rubin Baum Levin Constant & Friedman

                                       RUBIN BAUM LEVIN CONSTANT & FRIEDMAN