EXHIBIT 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Report of HERITAGE-CRYSTAL CLEAN, INC. (the “Company”) on Form 10-Q for the period ended September 8, 2018, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Brian Recatto, Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: October 18, 2018	By: /s/ Brian Recatto
	Brian Recatto
	President, CEO and Director — Principal Executive Officer