4. INVENTORIES

Inventories include the following:

	September 30, 2016		December 31, 2015
	(thousands of dollars)
Raw material	$	2,074	$	2,905
Work in process		72		56
Finished products		16,230		12,843
Total inventory	$	18,376	$	15,804

The difference between the calculated value of inventory under the FIFO and LIFO bases generates either a recorded LIFO reserve (i.e., where FIFO value exceeds the LIFO value) or an unrecorded negative LIFO reserve (i.e., where LIFO value exceeds the FIFO value). In the latter case, in order to ensure that inventory is reported at the lower of cost or market and in accordance with ASC 330-10, we do not increase the stated value of our inventory to the LIFO value.

At September 30, 2016, and December 31, 2015, LIFO value of petrochemical inventory exceeded FIFO; therefore, in accordance with the above policy, no LIFO reserve was recorded.

Inventory serves as collateral for our amended and restated credit agreement. See Note 9.

Inventory included petrochemical products in transit valued at approximately $2.8 million and $2.7 million at September 30, 2016, and December 31, 2015, respectively.