Evacuation or shelter? Disaster dictates safest move

This part of your disaster scenario deserves pre-planning

In the event of an accidental or intentional release of chemical, biological, or radiological contaminants, will employees and visitors at your workplace evacuate or take shelter where they are? The answer is determined by the substance and circumstances of release, and the decision is made by community emergency response directors, not by occupational health nurses in the workplace.

But the occ-health nurses can prepare employees and workplace for a stay-or-evacuate circumstance by first evaluating known potential risks, and then facilitating a plan to deal with the response appropriate should those risks become true emergencies.

"With any plan, the first thing is to know what kind of emergencies might affect your workplace, both internally and externally," says Erin Sarris, associate director for planning and preparedness for American Red Cross of Massachusetts Bay. "Is there some location near you that could have an accidental release into the air, such as a chlorine release, that would require sheltering in place?"

Sheltering in an emergency

Very simply, sheltering in place means retreating to a safe area where a safe air supply can best be secured in the immediate, short-term aftermath of a chemical or biological toxin release. The nature of the material released determines if the risks are greater staying in place or evacuating. For short-term threats, gathering employees and visitors in interior spaces where doors and air vents can be sealed against contamination is the simplest form of sheltering in place.

"Shelter in place" became a hot topic in disaster preparedness since the attacks of Sept. 11, 2001, and the advent of the Department of Homeland Security. People bought up plastic sheeting and duct tape in preparation for sealing themselves in their homes or offices in the event of a chemical or biological attack.

But Sarris says the need for sheltering in place is far more likely to arise from an accidental chemical release or accident than it is from terrorism.

Natural disasters, too — such as tornadoes — are other occurrences that can require a shelter-in-place plan. Sarris says these should be considered when evaluating what the risks are for your location.

Some examples of situations in which workplaces were forced to shelter employees include:

A Dow Chemical Co. accident in Plaquemine, LA, released chlorine. All Dow employees who stayed inside were unaffected; however, two employees who tried to evacuate from the cafeteria suffered respiratory problems from inhaling the chlorine;

A CSX rail car derailed near Miamisburg, OH, causing a release of liquid phosphorus. About 30,000 people were evacuated from the surrounding area, but a local hospital was unable to evacuate. The hospital staff and patients who sheltered in place were not injured;

A process vessel at a chemical plant in Nitro, WV, over-pressurized and released phosphorous chloride, which resulted in a hydrochloric acid cloud that drifted offsite into an adjacent office and commercial area. More than 800 employees of a neighboring plant, and several offices with employees who had been trained in sheltering in place took refuge indoors, and none were injured.

When to shelter in place

The decision to shelter in place is made by local authorities, based on an assessment of risk. Sarris says when a request to shelter in place comes down, workplaces need to have planned not only for the protection of their employees, but also for any visitors or customers who might be on the premises.

"You need to close your business, but you have to consider if you have customers and if you have employees who are out in the field," she points out. "And you need to communicate to the public via your voicemail that your doors are closed."

Preplanning not only means deciding where the safest place to shelter is, but also what steps to take and what materials to use to protect the ventilation system.

"Sheltering in place is short-term, so it is not a dramatic, bunkering-down thing," Sarris explains. "But talk with your employees about what their suggestions are and what supplies each individual should have."

National emergency preparedness entities like Red Cross rely on local emergency agents to quickly assess and make recommendations about disasters, she says.

"Local authorities make the decisions, and we place a great deal of hope and expectation on local authorities to get the message out quickly, so you do need to have battery powered radios, in case something happens that affects power," she says.

While the idea of sheltering in place may sound scary, Sarris says it happens on small cases "more frequently than you might think" in industrial areas.

The factors that go into a decision to shelter in place versus evacuate vary with the scenario. Among the considerations are the facility, the substance released, the time of day, and the realistic expectations of evacuating the population. (See Table for some factors weighed during a disaster.)

If local authorities request that your site shelter in place, that means everyone at the site, Sarris says. Customers, clients, or visitors to the building should be asked to stay, not leave. The shelter-in-place request is usually made when going outdoors is considered the least safe move.

In general, employees — and anyone else on the site —- cannot be forced to remain and shelter in place, according to the U.S. Federal Emergency Management Agency. However, there are some circumstances in which local officials can order that everyone remain where they are.

Employees should be informed of shelter-in-place and evacuation procedures, and understand their roles. Specific duties should be assigned in advance, with alternates designated and trained in case they have to fill in.

"Occupational health nurses should work with the company to create the plan, and then practice it," Sarris points out. "A plan is only as good as the people who carry it out."


Erin Sarris, associate director for planning and preparedness for emergency services, American Red Cross of Massachusetts Bay, Boston, MA. Phone (617) 274-5271.

Planning protective action decision-making: Evacuate or shelter-in-place? Oak Ridge (TN) National Laboratory for FEMA Chemical Stockpile Emergency Preparedness Program, 2002. Available online at www.emc.ornl.gov/EMCWeb/EMC/PDF/ornl_2002_144.pdf.

U.S. Department of Homeland Security, shelter-in-place planning for businesses. Online at www.ready.gov/business/plan/shelterplan.html.

National Institute for Chemical Studies, 2300 MacCorkle Avenue SE, Charleston, WV 25304. Online information on sheltering in place: www.nicsinfo.org.