Specialty chemical makers Momentive and Hexion, both controlled by the private equity firm Apollo Management, recently experienced what they call a “network security incident” that shut access to corporate computer systems. Hexion says the incident interrupted email and other systems. Momentive experienced similar issues. Press reports suggest that Hexion and Momentive were victims of LockerGoga, a ransomware program designed to block access to a computer system until a sum of money is paid. The virus also hit the aluminum maker Norsk Hydro at about the same time, reports say, compromising manufacturing operations. On March 26, a week after the attack, Norsk Hydro estimated the financial impact at $40 million. Both Hexion and Momentive say their manufacturing operations were mostly unaffected and continue to operate safely. Neither chemical firm tallied the cost of the attack. However, according to the online publication Motherboard, an internal email from Momentive CEO Jack Boss said data on affected computers was likely lost and that the company had ordered hundreds of new computers.