As of December 31,

2021

2020

(in thousands)

Accrued employee costs

$

30,935

$

28,404

Fuel and other taxes

31,381

29,817

Accrued insurance liabilities

10,986

8,139

Accrued expenses

35,672

36,485

Environmental liabilities

3,459

3,714

Deferred vendor income

11,654

11,328

Accrued income taxes payable

—

3,521

Due to related parties

258

144

Liabilities resulting from Additional and Contingent Consideration

8,813

9,569

Other accrued liabilities

4,330

2,516

Total other current liabilities

$

137,488

$

133,637