Tukes required the Talvivaara mining company to explain how it planned to reduce high concentrations of hydrogen sulphide in areas around the plant. Talvivaara has submitted a report to the chemicals watchdog, detailing improvements measures.
The metals factory is currently undergoing a maintenance shutdown, which is due to end by this weekend.
Tukes will carry out an inspection at Talvivaara after the Easter holiday. The results are to be released on April 16.
Tukes is meanwhile continuing their investigation into the death of a worker at the mine last month. High levels of hydrogen sulphide are suspected to have caused the death.