The income tax benefit attributable to continuing operations during the years ended December 31, 2019, 2018 and 2017 is as follows:

For the years ended December 31,	2019			2018			2017
(dollars in thousands)
Current (benefit) provision
Federal	$	(7	)	$	(1	)	$	(28	)
State		22			86			21
Deferred (benefit) provision
Federal		(279	)		2,100			114
State		(238	)		(250	)		568
Benefit related to a change in enacted tax law		-			-			(8,276	)
(Benefit) provision for income taxes	$	(502	)	$	1,935		$	(7,601	)

The income tax (benefit) provision reconciled to taxes computed at the statutory federal rate is as follows:

For the years ended December 31,		2019				2018				2017
Tax provision at statutory tax rate	$		792		$		2,645		$		3
State income taxes, net of federal impact			38				74				3
Research and development tax credit			(1,233	)			(874	)			(425	)
Valuation allowance, net of federal impact			(193	)			(167	)			475
Impact of changes in enacted tax law			-				-				(8,276	)
Adjustments to deferred taxes			41				277				506
Other, net			53				(20	)			113
(Benefit) provision for income taxes	$		(502	)	$		1,935		$		(7,601	)

We continue to record a full valuation allowance against our New York deferred tax assets due to the zero percent state income tax rate for qualified manufacturers. We continue to record a partial valuation allowance against our Pennsylvania net operating loss deferred tax asset due to annual usage limitations. We have determined that federal and other state deferred tax assets are expected to be realized and have not recorded any additional valuation allowances.

We recognized the tax effects of the Tax Cuts and Jobs Act (the “Tax Act”) in the year ended December 31, 2017 and recorded $8.3 million in tax benefits, which relates almost entirely to the remeasurement of deferred tax liabilities to the reduced 21% corporate income tax rate.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our net deferred taxes related to continuing operations are as follows:

December 31,	2019		2018
(dollars in thousands)
Noncurrent deferred income taxes:
Federal and state tax carryforwards	$	7,659	$	8,331
Inventory		970		787
Share-based compensation		2,029		1,909
Receivables		166		239
Accrued liabilities		333		836
Other		7		5
Total deferred tax assets	$	11,164	$	12,107
Deferred tax liabilities:
Property, plant and equipment	$	21,312	$	22,951
Other		814		637
Total deferred tax liabilities	$	22,126	$	23,588
Total noncurrent deferred income taxes	$	10,962	$	11,481

We file a U.S. federal income tax return and various state income tax returns. For federal income tax purposes, we had $8.6 million and $18.7 million of net operating loss carryforwards at December 31, 2019 and 2018, respectively. The net operating loss carryforwards begin to expire in 2031. In addition, we have credit carryforwards associated with our research and development activities of $5.2 million and $4.0 million as of December 31, 2019 and 2018, respectively. The research and development credit carryforwards begin to expire in 2030.

We have state net operating loss carryforwards of $8.8 million at December 31, 2019 and 2018, and the related valuation allowances were $2.8 million and $5.2 million at December 31, 2019 and 2018, respectively. We have state credit carryforwards of $0.2 million at December 31, 2019 and 2018. The state net operating loss carryforwards begin to expire in 2031. The state credit carryforwards begin to expire in 2027.

We are routinely under audit by federal or state authorities. Our federal tax returns are subject to examination by the IRS for tax years after 2015. We are subject to examination by most state tax jurisdictions for tax years after 2015.