X0306 4 2020-03-08 0001783400 US Ecology, Inc. ECOL 0001707338 Marshall Andrew 101 S. CAPITOL BLVD. SUITE 1000 BOISE ID 83702 1 EVP of Reg. Compl. & Safety Common Stock 2020-03-08 4 M 0 696 0 A 15552 D Restricted Stock Units 2020-03-08 4 M 0 696 0 D Common Stock 696 0 D Represents the conversion of Restricted Stock Units to common stock. On March 9, 2017, the reporting person was granted 2,090 Restricted Stock Units. Each Restricted Stock Unit represents the right to receive, at settlement, one share of common stock. On March 9, 2017, the reporting person was granted 2,090 Restricted Stock Units, of which 697 vested on each of March 8, 2018, and March 8, 2019. The 696 Restricted Stock Units reported in this Table II vested on March 8, 2020, and the common stock to which such Restricted Stock Units converted on March 8, 2020, is reported on Table I of this Form 4. /s/ Wayne Ipsen, Power of Attorney 2020-03-10