The following table sets forth the components of our regulatory assets and liabilities on our consolidated balance sheet (in thousands).

Regulatory Assets and Liabilities

	March 31, 2013		December 31, 2012
Regulatory Assets:
Current:
Under recovered purchased gas costs — gas segment(1)	$	764	$	1,689
Under recovered electric fuel and purchased power costs(1)	927		1,196
Other(1)	5,994		3,492
Regulatory assets, current(1)	7,685		6,377
Long-term:
Pension and other postretirement benefits(2)	133,539		136,480
Income taxes	47,297		48,759
Deferred construction accounting costs(3)	16,167		16,277
Unamortized loss on reacquired debt	10,910		11,078
Unsettled derivative losses — electric segment	4,748		6,557
System reliability — vegetation management	7,460		8,340
Storm costs(4)	4,437		4,223
Asset retirement obligation	4,492		4,430
Customer programs	3,756		3,916
Unamortized loss on interest rate derivative	978		989
Other	589		584
Deferred operating and maintenance expense	2,154		2,011
Under recovered electric fuel and purchased power costs	1,415		314
Regulatory assets, long-term	237,942		243,958
Total Regulatory Assets	$	245,627	$	250,335

	March 31, 2013		December 31, 2012
Regulatory Liabilities:
Current:
SWPA payment for Ozark Beach lost generation(1)	$	2,927	$	2,774
Other(1)	615		315
Regulatory liabilities, current(1)	3,542		3,089
Long-term:
Costs of removal	85,528		83,368
SWPA payment for Ozark Beach lost generation	18,583		19,467
Income taxes	11,617		11,972
Deferred construction accounting costs — fuel	7,975		8,011
Unamortized gain on interest rate derivative	3,328		3,371
Pension and other postretirement benefits(5)	1,635		2,007
Over recovered electric fuel and purchased power costs	5,954		5,826
Over recovered purchased gas costs — gas segment	1,908		247
Regulatory liabilities, long-term	136,528		134,269
Total Regulatory Liabilities	$	140,070	$	137,358

(1) Reflects over and under recovered costs of the current portion of regulatory assets or liabilities detailed in the long term sections below expected to be returned or recovered, as applicable, within the next 12 months in rates.

(2) Primarily reflects regulatory assets resulting from the unfunded portion of our pension and OPEB liabilities and regulatory accounting for EDG acquisition costs. Approximately $0.1 million in pension and other postretirement benefit costs have been recognized since January 1, 2013 to reflect the amortization of the regulatory assets that were recorded at the time of the EDG acquisition of the Aquila, Inc. gas properties.

(3) Balances as of March 31, 2013	Deferred Carrying Charges		Deferred O&M		Depreciation		Current			Total
Iatan 1	$	2,657	$	1,330	$	1,611	$	(171	)	$	5,427
Iatan 2	3,805		4,126		2,674		(224		)	10,381
Plum Point	64		183		158		(46		)	359
Total										$	16,167

Balances as of December 31, 2013	Deferred Carrying Charges		Deferred O&M		Depreciation		Current			Total
Iatan 1	$	2,678	$	1,339	$	1,622	$	(170	)	$	5,469
Iatan 2	3,821		4,155		2,685		(224		)	10,437
Plum Point	64		195		158		(46		)	371
Total										$	16,277

(4) Reflects ice storm costs incurred in 2007 and costs incurred as a result of the May 2011 tornado.

(5) Includes the effect of costs incurred that are more or less than those allowed in rates for the Missouri (EDE and EDG) and Kansas (EDE) portion of pension and other postretirement benefit costs. Since January 1, 2013, regulatory liabilities and corresponding expenses have been reduced by approximately $0.2 million as a result of ratemaking treatment.