In a situation where a serious hazardous chemical spill has quickly caused a toxic atmosphere, it may be more dangerous to go through those toxic vapors or to attempt to outrun them than to stay in an existing structure. Shelter-in-Place means to get to the inside of a building and remain there during a chemical emergency rather than attempting to evacuate the area. Shelter-in-Place is a viable option for protection against exposure to potentially dangerous airborne chemicals during an emergency.
During a hazardous materials incident, the idea is to keep everyone's exposure to any chemical as low as possible. It is best to get out of the area and have no exposure, but in a sudden chemical release there may not be time to safely evacuate. In such cases, attempts to evacuate could place you at greater risk of exposure than if you had stayed in your home or workplace.
Shelter-in-place is used when there has been a serious hazardous chemical spill that has quickly caused a toxic atmosphere and there is not enough time to safely leave the area. When you shelter-in-place, you take protective action in a structure to reduce exposure to toxic chemical levels. So, unless otherwise instructed to evacuate, sheltering-in-place could be the best way to safely wait out a hazardous chemical release.
In a 2001 report by The National Institute for Chemical Studies, several studies were cited that demonstrate the value of sheltering-in-place during a chemical emergency. In older homes, the average house was found to change its air at a rate of less than 1/3 change per hour. It was also found that if one room in the house was sealed up with duct tape and plastic, the amount of chemical that was in the room after one hour was between 1/7 to 1/17 of what was outside. Another study found that sealing up a house also filtered out some of the chemicals. Not only did a sealed up house limit the amount of air coming into a house, the walls actually did some filtering of the air that seeped in. Sheltering-in-place cannot completely eliminate all exposure to the chemical, but it can keep the exposure below dangerous levels.
The report concluded: "For the vast majority of events that have led to the public to shelter-in-place, there have been no reported injuries. In fact, for a very few cases, clouds of toxic materials of sufficient concentration to cause harm have entered communities and, because sheltering-in-place has been accepted by the community and was successfully implemented, no one was injured. The body of evidence suggests that if there is insufficient time to complete an evacuation, or the chemical leak will be of limited duration, or conditions would make an evacuation more risky than staying in place, sheltering-in-place is a good way to protect the public during chemical emergencies."
A hazardous materials accident can occur anywhere. There may even be a time when you are close to where a chemical accident has taken place. If you feel or hear a strange sound like an explosion; if you see a strange cloud; if you smell a strange odor; if you feel nauseous or have burning or tearing eyes; trust your senses, don't wait for a warning confirmation and act immediately. If it is obvious that you can safely evacuate the area, do so, but remember shelter-in-place as the next option.
In Buffalo County monitor:
If there is a chemical release in Buffalo County, the emergency alert system will be utilized. The outdoor warning sirens will sound to alert the public to turn on a radio or television for further emergency information.
If you are told to shelter-in-place or if you believe you need to, you should go inside any building close by immediately. If you are not by your own house, a church, school, or store are good options. If you are not near any buildings, your car is a better choice than staying outside. Your home is the best choice to shelter-in-place because you will know where tapes, towels, plastics and other items are located to help you create your shelter space.
If you can get to your car, go there. Turn off the ventilation system, close your windows and vents, and tune your radio to a local station. If you are driving, try to avoid driving through a vapor cloud and try to drive crosswind. If you are in a chemical cloud, be aware that your car may stall. If your car stalls or was not running when enveloped by the cloud, DO NOT try to start it unless told to do so by a public announcement on the radio.
If you are outside and not close to a building, such as being on a golf course or in a rural area, try to move crosswind. The vapors may drift downwind for miles and unless there is no wind at all you will not be able to outrun them. Going perpendicular to the wind, away from the center of the cloud will get you to a less harmful atmosphere quicker.
As soon as it is deemed safe, authorities will tell you it is safe to leave your building.
Special note: shelter-in-place does not apply to flammable gases such as propane and natural gases.