Homeland Security Secretary Janet Napolitano warned Thursday that a major cyber attack – the “cyber 9/11” – is a looming threat and could have the same sort of impact as last year’s Superstorm Sandy, which knocked out electricity in much of the Northeast, according to an article from Reuters.

Napolitano said such an event could happen “imminently” and that critical infrastructure – including water, electricity and gas – was vulnerable, the article says.

“We shouldn’t wait until there is a 9/11 in the cyber world. There are things we can and should be doing right now that, if not prevent, would mitigate the extent of damage,” Napolitano says, according to the article.

She has been urging Congress to pass legislation governing cyber security so the government could share information with the private sector to prevent a cyber attack on infrastructure. A cyber security bill failed in Congress last year after business and privacy groups opposed it, Reuters reports.

Business groups said that last year’s proposed legislation was government overreach. Privacy groups were concerned about Internet eavesdropping.

Without a new law, however, companies cannot be granted any legal immunity for sharing information with the government and within the industry about potential threats, the article says.

Officials have pointed to recent hacking attacks on U.S. banks as a sign that the cyber threat is real and growing, Reuters reports.

“The clarion call is here and we need to be dealing with this very urgently,” says Napolitano. “Attacks are coming all the time. They are coming from different sources, they take different forms. But they are increasing in seriousness and sophistication.”