Exhibit 3.1

AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

OF

AIRGAS, INC.

ARTICLE ONE

The name of the company is Airgas, Inc. (the “Company”).

ARTICLE TWO

The address of the registered office of the Company in the State of Delaware is Capitol Services, Inc., 1675 South State Street, #B, Dover, County of Kent, Delaware 19901. The name of the Company’s registered agent for service of process in the State of Delaware at such address is Capitol Services, Inc.

ARTICLE THREE

The purpose of the Company is to engage in any lawful act or activity for which a corporation may be organized under the General Corporation Law of the State of Delaware (the Delaware General Corporation Law”). The Company shall have perpetual existence.

ARTICLE FOUR

The total number of shares of stock which the Company is authorized to issue is 1,000 shares of common stock (the “Common Stock”). Each share of Common Stock shall have a par value of $0.01.

ARTICLE FIVE

The number of directors of the Company shall be such as from time to time fixed by, or in the manner provided in, the bylaws of the Company (the “Bylaws”). Unless, and except to the extent that, the Bylaws so require, the election of directors need not be by written ballot.

ARTICLE SIX

The board of directors of the Company (the “Board of Directors”) may from time to time adopt, amend or repeal the Bylaws, subject to the power of the stockholders to adopt any Bylaws or to amend or repeal any Bylaws adopted, amended or repealed by the Board of Directors.

ARTICLE SEVEN

A director of the Company shall not be personally liable to the Company or its stockholders for monetary damages for breach of fiduciary duty as a director, except for liability (i) for any breach of the director’s duty of loyalty to the Company or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of

law, (iii) under Section 174 of the Delaware General Corporation Law, or (iv) for any transaction from which the director derived an improper personal benefit. If the Delaware General Corporation Law is amended to authorize the further elimination or limitation of the liability of a director, then the liability of a director of the Company shall be eliminated or limited to the fullest extent permitted by the Delaware General Corporation Law, as so amended. Any repeal or modification of this Article Seven by the stockholders of the Company shall not adversely affect any right or protection of a director of the Company existing at the time of such repeal or modification.

ARTICLE EIGHT

The directors shall have powers without the assent or vote of the stockholders to fix and vary the amount to be reserved for any proper purpose; to authorize and cause to be executed mortgages and liens upon all or any part of the property of the Company; to determine the use and disposition of any surplus or net profits; and to fix the times for the declaration and payment of dividends.

ARTICLE NINE

The directors in their discretion may submit any contract or act for approval or ratification at any annual meeting of the stockholders or at any meeting of the stockholders called for the purpose of considering any such act or contract, and any contract or act that shall be approved or be ratified by the vote of the holders of a majority of the stock of the Company which is represented in person or by proxy at such meeting and entitled to vote thereat (provided that a lawful quorum of stockholders be there represented in person or by proxy) shall be as valid and as binding upon the Company and upon all the stockholders as though it had been approved or ratified by every stockholder of the Company, whether or not the contract or act would otherwise be open to legal attack because of directors’ interest or for any other reason.

ARTICLE TEN

In addition to the powers and authorities hereinbefore or by statute expressly conferred upon them, the directors are hereby empowered to exercise all such powers and do all such acts and things as may be exercised or done by the Company subject, nevertheless, to the provisions of the Delaware General Corporation Law, of this certificate of incorporation (the “Certificate”) and of any Bylaws from time to time made by the stockholders; provided, however, that no Bylaws so made shall invalidate any prior act of the directors which would have been valid if such Bylaw had not been made.

ARTICLE ELEVEN

The Company shall, to the full extent permitted by Section 145 of the Delaware General Corporation Law, as amended from time to time, indemnify all persons whom it may indemnify pursuant thereto.

ARTICLE TWELVE

Section 203 of the Delaware General Corporation Law shall not apply to the Company.

ARTICLE THIRTEEN

The Company reserves the right to amend, alter, change or repeal any provision contained in this Certificate in the manner now or hereafter prescribed by law, and, except as otherwise set forth herein or for the provisions of Article Seven and Article Eleven all rights and powers conferred herein on stockholders, directors and officers are subject to this reserved power.

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