The company also took lesser disciplinary measures against another 235 employees, spokesman Eric Grates said today. The company finished meting out the punishments this week, he said.
Dow Chemical fired those who handled the most explicit and graphic images, he said. The company began an investigation after an employee lodged a complaint.
Last month, the company said it expected to fire 40 employees for the incidents.
Some employees have objected to this and previous Dow investigations, complaining that the company scrutinizes email indiscriminately.
Though Dow doesn't routinely monitor employee email, Grates said, events such as a server running out of hard disk space can trigger an audit of servers and email systems.
The incidents took place at the company's Freeport, Texas, plant, which employs about 6,000 people. "We're dealing with a small percentage of people," he said.
The company's computer usage guidelines are posted on the corporate computer system and also are described in a "Respect and Responsibility" pamphlet, he said.