Power of Attorney
Know all by these presents, that the undersigned hereby constitutes and
appoints Roger Jackson, General Counsel of KMG Chemicals, Inc. (the
"Company"), the undersigned's true and lawful attorney-in-fact to:
(1)	execute for and on behalf of the undersigned, in the undersigned's
capacity as an officer of the Company, Forms 3, 4 and 5 in accordance
with Section 16(a) of the Securities Exchange Act of 1934, as amended,
and the rules thereunder;
(2)	do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete and execute any such
Form 3, 4 or 5 and timely file such form with the United States
Securities and Exchange Commission and any stock exchange or similar
authority; and
(3)	take any other action or any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of
benefit to, in the best interest of, or legally required by, the
undersigned, it being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant to this Power of
Attorney shall be in such form and shall contain such terms and
conditions as such attorney-in-fact may approve in such attorney-in-
fact's discretion.
The undersigned hereby grants to each attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary or proper to be done in the exercise of any of the rights and
powers herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this power of attorney and the
rights and powers herein granted.  The undersigned acknowledges that the
foregoing attorney-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming any of the
undersigned's responsibilities to comply with Section 16 of the Securities
Exchange Act of 1934.
This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4 and 5 with respect to
the undersigned's holdings of and transaction in securities issued by the
Company, unless earlier revoked by the undersigned in a signed writing
delivered to the foregoing attorneys-in fact.
IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of the 1st day of March, 2018.

/s/ Marvin T. Green, III
Marvin T. Green, III
L:\Corporate Records\Directors and Officers\Power of Attorney, Green.docx