Exhibit 5.1

[Calfee, Halter & Griswold LLP Letterhead]

October 29, 2009

Chart Industries, Inc.

One Infinity Corporate Centre Drive

Suite 300

Garfield Heights, Ohio 44125

Re: Chart Industries, Inc. 2009 Omnibus Equity Plan (the “Plan”)

We are familiar with the proceedings taken and proposed to be taken by Chart Industries, Inc., a Delaware corporation (the “Company”), with respect to 1,250,000 shares of common stock, par value $0.01 per share, of the Company (the “Shares”), to be offered and sold from time to time pursuant to the Plan. As counsel for the Company, we have assisted in the preparation of a Registration Statement on Form S-8 (the “Registration Statement”) to be filed by the Company with the Securities and Exchange Commission (the “Commission”) to effect the registration of the Shares under the Securities Act of 1933, as amended (the “Securities Act”).

In this connection, we have examined such documents, records and matters of law as we have deemed necessary or advisable for purposes of the opinions expressed herein.

In our examination of the foregoing documents, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as certified, photostatic or other copies, the authenticity of the originals of any such documents and the legal competence of all signatories to such documents.

We express no opinion herein as to the laws of any state or jurisdiction other than the General Corporation Law of the State of Delaware and the federal laws of the United States of America.

It is understood that this opinion is to be used only in connection with the offer and sale of the Shares while the Registration Statement is in effect.

Please note that we are opining only as to the matters expressly set forth herein, and no opinion should be inferred as to any other matters.

Based on the foregoing, we are of the opinion that the Shares have been duly authorized for issuance and, when the Shares are issued and paid for in accordance with the terms and conditions of the Plan, the Shares will be validly issued, fully paid and nonassessable.

We hereby consent to the filing of this opinion with the Commission in connection with the Registration Statement in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act. In giving such consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission.

Very truly yours,

/s/ Calfee, Halter & Griswold LLP

CALFEE, HALTER & GRISWOLD LLP

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