it's a very potent proxy force and the iranians know how to keep their fingerprints off an operation like this, but the suspicion as i said, fred, will be iran. >> so the two attacks alone have shut down half of saudi arabia's oil output. how vulnerable would saudi arabia be feeling about now? >> reporter: well, fred, it's hard to overestimate the effect of this attack because it's not just a fire that's the problem, it is release of poisonous gas, h 2 s, hid row general sulfide. it is deadly gas, will contaminate the infrastructure, and some estimates would put two years to repair it. so this is a catastrophe. >> and so what about endangering people that might live near