Explosives maker Orica will record $191 million in writedowns and impairments in next month’s first-half results.

Orica, which posted a $48.1 million full-year loss in 2018, says it will writedown the value of its Burrup amonia plant in WA by $155 million and take a $36 million pre-tax impairment against assets made obsolete by new software.

At 1038 AEST, Orica shares were down 17 cents, or 0.89 per cent, at $18.83.