Orica head Graeme Liebelt has publically apologised to the community around its Kooragang Island plant in a letter to Stockton and Fern Bay locals.
In the letter, the CEO of Orica also committed to an extensive upgrade of the embattled explosives plant, the Newcastle Herald reports.
This comes as the company carries out safety tests at the plant "prior to its consideration of lifting the prevention notices currently in place".
"The safety tests involve turning on the steam system to test its integrity.
"The steam will then be used to check a range of systems and to prove that the vent stack is clean of any contamination from the 8 August incident."
The explosives manufacturer closed its ammonium nitrate plant facilities on 9 November in response to an ammonia vapour leak from the site.
Its ammonia plant has been shut since an initial chemical leak in August.
Liebelt stated that Orica will invest between $12 million and $15 million annually over the next three years for a series of plant improvements.
It will also bring forward its ammonium nitrate expansion project.
One of the key aspects of the expansion project is a reduction of noise and gas emissions from the plant.
Liebelt explained that Orica is committed to changing the community’s perception of the company.