Homeland Security Secretary Michael Chertoff called for government regulation of chemical plant security on Tuesday but said the industry should come up with its own protective measures, to be verified by private auditors.

Speaking at a forum hosted by the chemical industry, Chertoff said Congress needs to quickly give his department regulatory authority to bolster facilities that are attractive targets for terrorists. But he said federal regulations must be flexible to prevent harsh burdens on business.

"We ought to say to the industry, 'Look, here's where we need to go,"' Chertoff said. "'Now, there are a lot of different roads to get there. And you can choose the road that best fits your particular kind of chemical, or your particular type of operation. We're not going to micromanage. What we do insist, though, is that you get to the place you need to be."'

Chertoff said he envisioned performance standards, set by the Homeland Security Department, for chemical companies to follow. Those standards would not require specific safeguards, such as gates and guards, but would force the industry to develop adequate security plans at all manufacturing and storage facilities.

Those standards could be validated by private auditors contracted with Homeland Security, Chertoff said.

Congress is considering legislation for federal regulation of the nation's 15,000 privately operated chemical facilities, which counterterror experts have warned are at the top of the list of likely terror targets. Congressional investigators have revealed spotty results in how well the chemical industry is prepared to respond in the event of an attack.

The leading bill, by Sens. Susan Collins, R-Maine, and Joseph Lieberman, D-Conn., would give Homeland Security authority to shut down plants that fail to submit acceptable security plans.

Large chemical corporations quickly applauded Chertoff's plans, which were mostly aimed at small firms that have resisted installing security because of high costs.

"What we're doing at Dow falls very much in line with what the secretary was talking about," said Tim Scott, chief security officer at Dow Chemical. "We approach security from a risk management perspective, and we try to identify the right level of risk and the right approach to reduce that risk at all of our sites."

Chertoff said he did not think any regulation should require the chemical industry to use certain kinds of substances that would be less dangerous to the public in an attack or accidental release, as environmentalists have demanded.

"We have to be careful not to move from what is a security-based focus, as far as the type of regulation I'm describing, into one that tries to broaden into achieving environmental ends that are unrelated to security," he said.

But with one-fifth of the nation's chemical plants located close to cities and other heavily populated areas, "there isn't any security that would be good enough" against the threat of a hazardous toxic release, said Greenpeace legislative director Rick Hind said Monday. "A small plane or a high powered weapon would bypass any gate or fence."