Inventories

The major components of inventories were as follows:



	March 31, 2019		December 31, 2018
Petroleum products	$	4,585	$	12,203
Crude oil	24,238		8,379
Caustic soda	8,040		10,372
NaHS	8,632		12,400
Raw materials - Alkali operations	6,401		5,952
Work-in-process - Alkali operations	6,343		2,322
Finished goods, net - Alkali operations	10,941		11,402
Materials and supplies, net - Alkali operations	10,967		10,490
Other	—		11
Total	$	80,147	$	73,531

Inventories are valued at the lower of cost or net realizable value. The net realizable value of inventories were not recorded below cost as of March 31, 2019 and were recorded below cost by $1.0 million as of December 31, 2018.