v2.4.0.6
ACCRUED LIABILITIES
12 Months Ended
Dec. 31, 2011
Accrued Liabilities [Abstract]  
Accrued Liabilities
ACCRUED LIABILITIES
Accrued liabilities consisted of the following:
 
December 31,
 
2011
 
2010
 
(Thousands of Dollars)
Employee wages and benefit costs
$
24,325

 
$
21,216

Derivative liabilities
27,433

 
14,741

Unearned income
8,866

 
4,375

Environmental costs
3,312

 
2,659

Product imbalances
1,469

 
988

Other
5,865

 
13,974

Accrued liabilities
$
71,270

 
$
57,953