REVENUES (Tables)

3 Months Ended

Mar. 31, 2022

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

The following tables present the Company's third-party revenue disaggregated by source of revenue and geography (in thousands):

	For the Three Months Ended March 31, 2022
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	834,678	$	202,530	$	72	$	1,037,280
Canada	106,120		25,709		—		131,829
Total third-party revenues	$	940,798	$	228,239	$	72	$	1,169,109
Sources of Revenue
Technical Services	$	323,656	$	—	$	—	$	323,656
Field and Emergency Response Services (1)	132,359		—		—		132,359
Industrial Services and Other (2)	308,838		—		72		308,910
Safety-Kleen Environmental Services	175,945		44,388		—		220,333
Safety-Kleen Oil	—		183,851		—		183,851
Total third-party revenues	$	940,798	$	228,239	$	72	$	1,169,109

_____________

(1) Includes approximately $28.0 million of third-party revenues from the operations of the HydroChemPSC business

(2) Includes approximately $156.1 million of third-party revenues from the operations of the HydroChemPSC business

	For the Three Months Ended March 31, 2021
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	575,508	$	138,990	$	79	$	714,577
Canada	77,370		16,201		—		93,571
Total third-party revenues	$	652,878	$	155,191	$	79	$	808,148
Sources of Revenue
Technical Services	$	272,040	$	—	$	—	$	272,040
Field and Emergency Response Services	105,168		—		—		105,168
Industrial Services and Other	119,810		—		79		119,889
Safety-Kleen Environmental Services	155,860		38,978		—		194,838
Safety-Kleen Oil	—		116,213		—		116,213
Total third-party revenues	$	652,878	$	155,191	$	79	$	808,148

Schedule of Contract Balances

(in thousands)	March 31, 2022		December 31, 2021
Receivables	$	900,273	$	792,734
Contract assets (unbilled receivables)	123,945		94,963
Contract liabilities (deferred revenue)	90,116		83,749