The Homeland Security Department has posted a guide to help businesses to prepare for terrorist attacks and natural disasters at www.ready.gov/business.

The guidelines concentrate on preparing and responding to biological, chemical, nuclear and radiological attacks, but many of the tips apply in other sorts of emergencies.

The department also released a fact sheet estimating the cost of some of the steps it recommends. It says many of the steps, such as taking inventory and maintaining a list of emergency contractors, cost nothing. Others, such as offering first-aid training to employees, can be done for less than $500.

Some of the tips are more than obvious – “Involve co-workers.”

The site offers a sample emergency plan with a checklist business owners can use to make sure they touch all the bases in preparing for the worst.

“Small to medium-sized businesses in particular are most vulnerable following a disaster,” the department said in announcing the initiative. “Having an emergency plan can help protect a company and maximize its potential for survival.”

DHS pointed to a statement by the 9-11 Commission: “Private-sector preparedness is not a luxury; it is a cost of doing business in the post-9-11 world. It is ignored at a tremendous potential cost in lives, money, and national security.”