“We have seen that disruptions to supply chains caused by natural disasters -- earthquakes, tsunamis and volcanic eruptions -- and from criminal and terrorist networks seeking to exploit the system or use it as a means of attack can adversely impact global economic growth and productivity,” Obama said in a letter released by the White House .

Obama directed department officials to confer with state, federal and international government agencies and private industry to identify areas that are most at risk and come up with layered defenses and tightened security steps to guard against disruptions, the letter says.