11. Other long‑term liabilities

Other long‑term liabilities consist of the following at December 31:


	2019		2018
Long-term contract liability	$	0.2	$	—
Net pension liability		1.2		1.2
Accrued LTIP and director share units		1.6		1.4
Other		1.7		2.4
	$	4.7	$	5.0

The following table is a rollforward of asset retirement obligations for the years ended December 31:


	2019		2018
Asset retirement obligations beginning of year	$	49.2	$	45.3
Accretion and change in estimate of asset retirement obligation		2.3		4.3
Acquisition		—		1.8
Costs incurred		(1.0)		(0.5)
Translation adjustments		1.0		(1.7)
Asset retirement obligations, end of year	$	51.5	$	49.2

In the third quarter of 2017, we performed an event-driven long-lived asset impairment test at our Naval Station, North Island and Naval Training Center projects. See Note 8, Property, plant and equipment for discussion of the facts and circumstances resulting in the impairment. At the time of the assessment, we had not completed our process for estimating decommissioning costs at those facilities. In the fourth quarter of 2017, based on information provided by third parties, we determined that the estimated costs to remove the facilities and return the land to the conditions required under their respective land rights agreements was approximately $1.7 million. Prior to adjustment, we had recorded asset retirement obligations for Naval Station, North Island and Naval Training Center of $6.7 million. These retirement obligations were based on estimates made at the time of their acquisition in November 2011, as well as engineering studies performed at the inception of these projects. These asset retirement obligations were accreted based on inflation and discount rates. As a result of the change in estimate for decommissioning costs, we recorded a $5.0 million decrease to amortization expense in the fourth quarter of 2017. These projects ceased operations in February 2018. Subsequent to their shutdown, we have been actively planning the decommissioning of these facilities. Although the process is not final, changes to both the scope and cost of decommissioning these facilities resulted in a change of estimate of the asset retirement obligation. We increased the asset retirement obligation by $1.4 million and $3.5 million and recorded a corresponding decommissioning loss in the consolidated statements of operations for the years ended December 31, 2019 and 2018, respectively.