Note L - Business Segment and Geographic Disclosures (Tables)

3 Months Ended

Mar. 31, 2013

Schedule of Segment Reporting Information, by Segment [Table Text Block]

Three months ended March 31, 2013	Air Pollution Control Segment			FUEL CHEM Segment			Other			Total
Revenues from external customers	$	12,947		$	9,537		$	-		$	22,484
Cost of sales		(8,583	)		(4,469	)		-			(13,052	)
Gross margin		4,364			5,068			-			9,432
Selling, general and administrative		-			-			(8,458	)		(8,458	)
Research and development		-			-			(933	)		(933	)
Operating income	$	4,364		$	5,068		$	(9,391	)	$	41

Three months ended March 31, 2012	Air Pollution Control Segment			FUEL CHEM Segment			Other			Total
Revenues from external customers	$	15,714		$	9,498		$	-		$	25,212
Cost of sales		(8,751	)		(4,469	)		-			(13,220	)
Gross margin		6,963			5,029			-			11,992
Selling, general and administrative		-			-			(8,994	)		(8,994	)
Research and development		-			-			(506	)		(506	)
Operating income	$	6,963		$	5,029		$	(9,500	)	$	2,492

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

	Three months ended March 31,
	2013		2012
Revenues:
United States	$	12,866	$	22,944
Foreign		9,618		2,268
	$	22,484	$	25,212

Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]

	March 31, 2013		December 31, 2012
Assets:
United States	$	85,182	$	86,466
Foreign		18,478		19,431
	$	103,660	$	105,897