The incident occurred at the Bristol Myers Squibb (BMS) factory in Swords, Dublin, at approximately 7:30am.
According to a spokesperson for the plant, the event involved “a small localised chemical leak from a manufacturing vessel”.
The onsite emergency response team immediately dealt with the issue, but eight workers displayed symptoms consistent with a reaction to the leak, so they were taken to Beaumont Hospital for treatment.
All eight are currently under medical supervision, and have been retained for observation.
A full investigation into the cause of the leak has been launched by the appropriate authorities.