Annual report pursuant to Section 13 and 15(d)

Property and equipment, net

Property and equipment, net
12 Months Ended
Dec. 31, 2019
Property, Plant and Equipment [Abstract]  
Property and equipment, net
5. Property and equipment, net
Property and equipment, net, consisted of the following (in thousands):

  Useful Life (Years) December 31,
Asset Class

Operational equipment
$ 12,094    $ 15,926   
Lab equipment 5 525    698   
Computer equipment 3 221    201   
Office furniture and equipment 3 221    336   
Land 1,047    1,047   
Building 39 19,508    24,820   
Asset retirement cost 20 670    670   
Equipment under construction 9,921    7,892   
  44,207    51,590   
Less:  accumulated depreciation (6,564)   (6,042)  
  $ 37,643    $ 45,548   

Depreciation expense was $3.5 million and $3.2 million for the years ended December 31, 2019 and December 31, 2018, respectively. The building is a 136,750 square foot lead acid battery recycling plant built in McCarran, Nevada. Equipment under construction is comprised of various components being manufactured or installed by the Company, to be used in the McCarran, Nevada recycling plant.
The Company has financed certain equipment purchases through the use of capital leases. The lease terms are generally between 24 and 36 months with an option to purchase the asset at the end of the lease for $1. Total equipment included in the above table, subject to capital leases, is immaterial to our consolidated financial statements at December 31, 2019. Total equipment included in the above table at December 31, 2018 subject to capital leases is $0.4 million less accumulated depreciation of $0.2 million, resulting in net fixed assets under capital lease of $0.2 million. These assets are depreciated using the same useful lives as noted above and included in depreciation expense.

On November 29, 2019, there was a fire in the AquaRefining area of the plant. As a result of the fire, the company wrote off approximately $22.4 million of fixed assets that were damaged. These assets consisted of operational equipment, building and equipment under construction. The disposal of the fire damaged fixed assets included a decrease of accumulated depreciation of $2.5 million. The net write-off of fixed assets totaled $19.9 million.