Dry Ice Fog for Halloween and Parties: How to Do It Safely
Nothing sets a Halloween scene like thick, low fog rolling across the floor. Dry ice makes that effect. Here is how to do it, how much you need, and the safety rules you must follow.
How dry ice fog works
Dry ice is solid carbon dioxide at about −78.5°C. When you put it into warm or hot water it turns into gas very quickly, and the cold gas makes water vapour condense into a thick white fog. Because the fog is cold and heavy, it stays low and flows across floors and down steps.
Making fog without a machine
- Use a sturdy bucket, cauldron or heat-safe bowl (never a sealed container).
- Fill it about half full with hot water (not boiling, to avoid splashes).
- Wearing insulated gloves, add a few pieces of dry ice using tongs.
- The fog lasts a few minutes; as the water cools, the fog slows. Top up with hot water and add more dry ice as needed.
Using a dry ice fog machine
Dry ice fog machines (also called low fog machines) heat water in a tank and lower a basket of dry ice into it, giving a controlled, longer-lasting effect for events, stages and first dances. Follow the manufacturer's instructions for water level and how much dry ice to load.
How much dry ice do you need?
Dry ice disappears fast in hot water: expect a few kilos per hour of continuous fog, more for large rooms or machines. For an evening party with fog for an hour or two, 10 kg (our minimum order) is a sensible start. Remember it also shrinks in storage; see how long dry ice lasts.
Safety rules (important)
- Ventilation: dry ice fog is carbon dioxide. Use it only in well-ventilated spaces, never in small closed rooms, cellars or tents without airflow.
- Keep heads above the fog: CO2 collects at floor level. Never let children or pets lie down or play in the fog, and keep fog away from cots, pet beds and low seating.
- Never touch it: handle dry ice only with insulated gloves or tongs.
- Never in drinks or food: do not add dry ice to punch, cocktails or food, even for effect. Swallowing it can cause serious internal injuries.
- Never seal it: airtight containers can burst.
- Read our full dry ice safety and handling guide.
Ordering dry ice in London
- 5 kg packs, £45 each; minimum 10 kg (2 packs).
- Order at least 2 days ahead. For Halloween on Saturday 31 October, order by 5pm on Thursday 29 October.
- Read our dry ice safety and handling guide; you confirm this at checkout.
- Order dry ice or see dry ice delivery London.
Dry ice turns into gas from the moment it is packed, so the weight delivered can be lower than the weight ordered. Nice Ice is not responsible for weight loss caused by sublimation.
Need ice for drinks too? See party ice delivery London.
Frequently asked questions
How do you make fog with dry ice? Put pieces of dry ice into warm or hot water in an open container. The cold carbon dioxide gas creates a thick low-lying fog.
How much dry ice do I need for Halloween fog? Allow a few kilos per hour of continuous fog. 10 kg is a sensible amount for a party with fog for an hour or two.
Is dry ice fog safe? It is safe in well-ventilated spaces when handled properly. Keep children and pets out of the fog, never use it in small closed rooms, and never put dry ice in drinks or food.
When should I order dry ice for Halloween? We need at least 2 days' notice. For Saturday 31 October, order by 5pm on Thursday 29 October.