As of December 31,

2023

2022

(in thousands)

Accrued employee costs

$

22,015

$

28,298

Fuel and other taxes

40,392

30,491

Accrued insurance liabilities

10,464

9,881

Accrued expenses

50,798

42,955

Environmental liabilities

4,100

3,425

Deferred vendor income

13,134

12,101

Accrued income taxes payable

—

4,056

Liabilities resulting from Additional and Contingent Consideration

5,524

5,674

Deferred payments related to acquisitions (see Note 4)

25,291

—

Ares Put Option

—

8,575

Other accrued liabilities

7,818

8,641

Total other current liabilities

$

179,536

$

154,097