A shelter in place order in Houston means an outdoor hazard, usually a chemical release from a Ship Channel facility or severe weather, makes it safer to stay indoors than to leave. When one is issued for your area, get inside immediately, follow the procedure that matches the threat, and stay put until authorities give an official all-clear. The actions for a chemical release and a tornado are almost opposite, so the first thing to know is which kind of event you are in.
Chemical Release and Severe Weather Call for Different Actions
For a chemical or industrial release, the goal is keeping contaminated outside air out of the space around you. You move to an interior room, shut down anything that pulls air in, and seal the room with plastic sheeting and tape. These events usually last a few hours.
For a tornado, sealing a room does nothing. The threat is wind and flying debris. You go to the lowest level of a sturdy building, find a small interior room without windows, and shield your head and neck with your arms or blankets. Furniture can add cover. You stay there until weather forecasts confirm the threat has passed.1FEMA.gov. Shelter-in-Place Pictogram Guidance
Mixing the two up is dangerous. Sealing a room during a tornado wastes time you need for taking cover; running to a basement during a chemical release can expose you to heavier-than-air vapors. Confirm which kind of alert you have received before you act.
How to Seal a Room During a Chemical Release
Speed matters. Once the alert hits, bring everyone, pets included, indoors. Close and lock all exterior doors and windows; locking creates a tighter seal than just closing. Move everyone to a pre-selected interior room, ideally above ground level with as few windows and doors as possible.1FEMA.gov. Shelter-in-Place Pictogram Guidance
Shut off every heating, ventilation, and air conditioning system in the house. These actively draw outside air in. Close the fireplace damper. Then apply plastic sheeting over every window, vent, and recessed fan in the room, taping down all edges. Tape over electrical outlets too, since they connect to wall cavities that pull air. Seal the gap under the door with tape last.1FEMA.gov. Shelter-in-Place Pictogram Guidance
The Department of Homeland Security recommends plastic sheeting of 4 to 6 mil thickness or greater.2FEMA.gov. Type of Plastic Sheeting to Use for Shelter-in-Place Pre-cut it to fit your safe room’s windows and vents before you ever need it, so you aren’t measuring during an emergency.
Do not drink tap water during a chemical shelter-in-place event. Stored water is safer, because treatment systems may be affected by the same contaminant you are sheltering from.1FEMA.gov. Shelter-in-Place Pictogram Guidance
If You Are Caught Outside or in a Car
Vehicles are not safe shelters for chemical events. The CDC warns that cars, trucks, and other vehicles are generally not airtight enough to protect you from airborne chemical hazards.3CDC. What to Do to Shelter in Place for a Chemical Emergency If an alert comes through while you are driving, find the nearest solid building and get inside. Check your phone or radio for shelter locations.
If no building is reachable and you must stay in the vehicle, turn off the engine, close all windows and vents, and switch the air system to recirculate rather than drawing outside air. This is a stopgap, not a substitute for a real structure. Follow instructions from police or fire officials about where to go.
How You Will Be Notified
AlertHouston is the city’s primary notification system. It delivers geo-targeted alerts by email, text message, voice call, and mobile app push notifications. You can register up to five physical addresses per account, which helps if family members live in different parts of the city.4City of Houston Emergency Operations Center. Emergency Alerts Registration is free through the Houston Emergency Operations Center website.
AlertHouston runs alongside the federal Integrated Public Alert and Warning System (IPAWS), which pushes Wireless Emergency Alerts directly to compatible cell phones in a defined area. These arrive even if you haven’t registered for anything.5City of Houston Office of Emergency Management. City of Houston to Conduct City-Wide Wireless Emergency Alert System Test Local television and radio stations also carry Emergency Alert System broadcasts during active events.
If you or someone in your household has a disability, limited mobility, medical equipment that needs power, or other functional needs, sign up for the State of Texas Emergency Assistance Registry (STEAR). The free program connects you with local emergency planners. Registration doesn’t guarantee specific services, but it puts your needs on responders’ radar before an emergency hits. Sign up at stear.texas.gov or by calling 2-1-1. The registry asks for your name, address, phone number, primary language, specific needs, emergency contacts, pets, and transportation requirements.6Texas Division of Emergency Management. State of Texas Emergency Assistance Registry
Supplies to Have Ready Before an Alert
Once an order is issued, you won’t be able to leave to buy anything, and power or water service may go down. Keep everything in one accessible spot so you can act fast.
Sealing Materials and Communication
For chemical events, keep plastic sheeting of at least 4 to 6 mil and a roll of duct tape set aside, with the sheeting pre-cut for your safe room. A battery-powered or hand-crank weather radio keeps you connected if the power fails and your phone dies.
Water, Food, and Medications
Ready.gov recommends storing at least one gallon of water per person per day for several days, covering drinking and basic sanitation.7Ready.gov. Water Stock non-perishable food that needs no cooking or refrigeration. Keep a supply of prescription medications on hand, along with over-the-counter basics. If anyone in your household wears prescription eyeglasses or contact lenses, keep backups with the kit.8Ready.gov. Build A Kit
Sanitation and First Aid
Ready.gov’s recommended kit includes moist towelettes, garbage bags, plastic ties, soap, hand sanitizer, and disinfecting wipes. Add a basic first aid kit and a dust mask for each household member. Households with infants should stock formula, bottles, diapers, and diaper cream separately.8Ready.gov. Build A Kit
Pet Supplies
Ready.gov recommends keeping several days of pet food in a waterproof container, a water bowl and water supply, any regular medications, and a first aid kit for your animal. Keep a carrier or crate for each pet, plus pet litter, newspapers, and trash bags. A photo of you with your pet helps prove ownership if you get separated. A familiar toy or blanket can reduce stress for an animal that senses something is off.9Ready.gov. Prepare Your Pets for Disasters
After the All-Clear
The order stays in effect until authorities issue an all-clear through the same channels that delivered the alert: AlertHouston, Wireless Emergency Alerts, and local broadcast media. In some industrial areas, outdoor warning sirens sound a steady tone to signal the hazard has passed. Do not unseal your room based on social media rumors or because conditions seem fine. Chemical contaminants are often invisible and odorless at dangerous concentrations.
Once the all-clear comes, remove the plastic sheeting and tape. Open windows and doors to ventilate the house. Turn the HVAC back on to flush the indoor air. If you had any symptoms during the event, such as difficulty breathing, burning eyes, or nausea, seek medical attention even after the all-clear. Some chemical exposures have delayed effects.
If a Shelter-in-Place Order Hits While You Are at Work
Under the General Duty Clause of the Occupational Safety and Health Act, employers must provide a workplace free from recognized hazards likely to cause death or serious physical harm. That includes having a plan for chemical emergencies in areas where industrial releases are a known risk.10Occupational Safety and Health Administration. Mass Care Shelter Occupational Hazards
On pay, the Fair Labor Standards Act requires employers to pay non-exempt employees for all hours actually worked, including time spent sheltering at the workplace. That requirement is not waived during natural disasters or emergencies. The FLSA does not require employers to pay non-exempt workers for hours they would have worked if the employer couldn’t provide work because of the disaster.11U.S. Department of Labor. Fact Sheet: Employment and Wages Under Federal Law During Natural Disasters and Recovery The practical line: if you are stuck at work doing anything (answering phones, helping secure the building), that is compensable time. If the business shuts down and you are only waiting it out, the answer is less clear and may depend on your employment agreement.
Is a Shelter-in-Place Order Mandatory?
Yes. Houston Code of Ordinances Chapter 13 authorizes the Mayor to issue executive orders necessary to protect public health and safety after declaring a local state of disaster. Those orders can make specific conduct unlawful for the duration of the emergency and remain in effect until the Mayor rescinds them, the disaster declaration expires, or City Council terminates them by ordinance.12Municode Library. Houston Code of Ordinances Chapter 13 – Emergency Management
Texas Government Code Section 418.173 sets the maximum penalty for violating an emergency management plan: a fine up to $1,000, jail time up to 180 days, or both.13State of Texas. Texas Government Code 418.173 – Penalty for Violation of Emergency Management Plan Enforcement during Houston shelter-in-place events has focused on keeping people safe rather than issuing citations, but the authority exists.