Campus Oil is now Certa! Certa Ireland is a subsidiary of DCC plc. DCC plc is a leading international sales, marketing and support services group operating in 23 countries, supplying products and services used by millions of people every day. Headquartered in Dublin, the Group operates across three sectors: energy, healthcare and technology, employing over 16,000 people. DCC plc is listed on the London Stock Exchange and is a constituent of the FTSE 100.