Corden Pharma Ltd has been fined €300,000 following a chemicial explosion at the Cork plant four years ago in which one employee was killed.
A second employee was seriously injured in the incident at the Little Island plant on April 28, 2008.
The company, which is no longer operating at the site, pleaded guilty to four separate charges under the Safety, Health and Welfare at Work Act.
Costs of more than €27,000 and €45,000 were also awarded to the Health and Safety Authority and the DPP.
Speaking after the fine was handed down, the HSA said: "Whether manufacturing or using chemicals in the production of other products, it is critical that a comprehensive risk assessment is undertaken and appropriate precautions put in place."