Inventories

The major components of inventories were as follows:



	June 30, 2018		December 31, 2017
Petroleum products	$	5,490	$	8,731
Crude oil	29,930		29,873
Caustic soda	6,964		5,755
NaHS	13,040		8,277
Raw materials - Alkali operations	4,396		4,550
Work-in-process - Alkali operations	11,114		7,355
Finished goods, net - Alkali operations	11,182		14,075
Materials and supplies, net - Alkali operations	10,403		10,030
Other	1		7
Total	$	92,520	$	88,653

Inventories are valued at the lower of cost or net realizable value. The net realizable value of inventories was not below cost as of June 30, 2018 and December 31, 2017.