Inventories

12 Months Ended

Dec. 31, 2022

Inventories are valued at the lower of cost (using the first-in, first-out and weighted average methods) or market. The Company's costs included in inventory primarily include resins, pulp, chemicals, direct labor, utilities, maintenance, depreciation, finishing supplies and an allocation of certain overhead costs. Machine start-up costs or abnormal machine shutdowns are expensed in the period incurred and are not reflected in inventory. The definition of market value, with respect to all inventories, is net realizable value. The Company reviews inventories at least quarterly to determine the necessity of write-offs for excess, obsolete or unsalable inventory. The Company estimates write-offs for inventory obsolescence and shrinkage based on its judgment of future realization. These reviews require the Company to assess customer and market demand. During the years ended December 31, 2022, 2021, and 2020, there were no material inventory write-offs.

The following table summarizes our inventories by major class (in millions):


	December 31,
	2022		2021
Raw materials	$	206.0	$	113.4
Work in process	80.5		41.9
Finished goods	223.9		95.7
Supplies and other	24.5		8.5
Inventories	$	534.9	$	259.5