EXHIBIT 5.1 Blake, Cassels & Graydon LLP Box 25, Commerce Court West 199 Bay Street Toronto, Ontario, Canada MSL 1A9 Deliveries: 28th Floor Telephone: 416.863.2400 Facsimile: 416.863.2653 www.blakes.com April 26, 2002 Reference: 58974/1 DELIVERED - --------- Capital Environmental Resource Inc. 1005 Skyview Drive Burlington, Ontario Canada L7P 5B1 Dear Sir or Madam: RE: REGISTRATION STATEMENT ON FORM S-8 RELATING TO THE 1999 STOCK OPTION PLAN (THE "PLAN") --------------------------------------------------------- Reference is made to the above-captioned Registration Statement on Form S-8 (the "Registration Statement") filed by Capital Environmental Resource Inc. (the "Company") on the date hereof with the Securities and Exchange Commission under the Securities Act of 1933 relating to an aggregate of 6,653,302 common shares of the Company issuable pursuant to the Plan (the "Shares"). We have examined, and are familiar with, and have relied as to factual matters solely upon, a copy of the Plan, the currently effective articles and by-laws of the Company and originals of such other documents, certificates and proceedings as we have deemed necessary for the purpose of rendering this opinion. Based on the foregoing, we are of the opinion that the Shares have been duly authorized and, when issued and paid for in accordance with the terms of the Plan and the terms of any agreement relating to any of the options granted thereunder, will be legally issued, fully paid and non-assessable. We hereby consent to the filing of this opinion as Exhibit 5.1 to the Registration Statement. Yours truly, /s/ Blake, Cassels & Graydon LLP