EXHIBIT 3

                                                               December 13, 1995
 
To Our Stockholders:
 
    On behalf of the Board of Directors of The Earth Technology Corporation
(USA), I am pleased to inform you that on December 8, 1995, the Company entered
into an Agreement and Plan of Merger with Tyco International Ltd., a
Massachusetts corporation and T1 Acquisition Corp. (the "Purchaser"), a Delaware
corporation and wholly owned subsidiary of Tyco. Pursuant to the Merger
Agreement, the Purchaser has today commenced a cash tender offer to purchase all
outstanding shares of common stock, par value $.10 per share, of the Company
(the "Shares")for $8.00 per Share. Under the Merger Agreement, the Offer will be
followed by a merger of the Purchaser with and into the Company pursuant to
which any remaining Shares will be converted into the right to receive $8.00 per
Share in cash, without interest. We believe that this offer represents superior
value for our stockholders and a tremendous opportunity for continued growth of
the Company.
 
    YOUR BOARD OF DIRECTORS HAS DETERMINED THAT THE OFFER AND THE MERGER ARE
FAIR TO, AND IN THE BEST INTERESTS OF, THE COMPANY AND ITS STOCKHOLDERS, HAS
APPROVED THE MERGER AGREEMENT, THE OFFER AND THE MERGER, AND RECOMMENDS THAT THE
COMPANY'S STOCKHOLDERS ACCEPT THE OFFER AND TENDER THEIR SHARES PURSUANT TO THE
OFFER.
 
    In arriving at its recommendation, the Board of Directors gave careful
consideration to the factors described in the attached
Recommendation/Solicitation Statement on Schedule 14D-9 that is being filed
today with the Securities and Exchange Commission, including the opinion of
Alex. Brown & Sons Incorporated, the Company's financial advisor, to the effect
that the consideration to be received by the stockholders pursuant to the Offer
and the Merger is fair to such holders from a financial point of view.
 
    In addition to the attached Schedule 14D-9, also enclosed is the Offer to
Purchase, dated December 13, 1995, of the Purchaser, together with related
materials including a Letter of Transmittal, to be used for tendering your
Shares. These documents set forth the terms and conditions of the Offer and the
Merger and provide instructions as to how to tender your Shares. I urge you to
read the enclosed material carefully.
 
                                      Sincerely,

                                      /s/ Diane C. Creel

                                      Diane C. Creel
                                      Chairwoman of the Board,
                                      Chief Executive Officer and President