Disposable dry ice block for fish is an essential tool for anyone shipping or transporting seafood. By using solid carbon dioxide (CO₂) that sublimates at –78.5 °C (–109.3 °F), these blocks keep fish at consistently low temperatures without melting into water. In this guide you’ll learn what a disposable dry ice block for fish is, how it works, why it’s better than regular ice, and how to use it safely. You’ll also see the latest trends and sustainable alternatives emerging in 2025. Whether you run a seafood business or just need to ship fresh fish, this article will help you keep your products fresh while meeting modern regulations and environmental goals.
What is a disposable dry ice block for fish and how does it work? – explains the physics and why dry ice sublimates.
Why choose a disposable dry ice block for fish? – covers benefits like extended cooling and no residue.
How to use disposable dry ice blocks for fish safely and effectively? – includes sizing, packing layers, ventilation and disposal.
Are there sustainable alternatives to disposable dry ice blocks for fish? – explores fiber boxes and biodegradable packs.
What trends shape the disposable dry ice block for fish in 2025? – looks at smart sensors, hybrid systems and eco friendly materials.
What Is a Disposable Dry Ice Block for Fish and How Does It Work?
A disposable dry ice block for fish is a pre formed block of solid carbon dioxide designed to keep seafood at ultra cold temperatures during transport. Dry ice is frozen CO₂ that sublimates directly from a solid to a gas at –78.5 °C. Unlike regular water ice, it does not melt into liquid, so fish remain dry and uncontaminated. When used in an insulated box, the dry ice absorbs heat as it sublimates, creating a cold environment that reduces oxidation and microbial growth. Because it releases gas instead of water, the block leaves no moisture residue and prevents fish from becoming soggy.
How Dry Ice Blocks Differ from Gel and PCM Packs
| Cooling Medium | Typical Temperature Range | Regulatory Classification | Residue After Use | Best Use Cases | Practical Meaning |
| Disposable dry ice block | ~–78.5 °C to –20 °C | Class 9 hazardous material (UN 1845) | Sublimates to CO₂ gas (no liquid) | Frozen fish, biologics, specialty seafood | Maintains deep freeze conditions without moisture |
| Gel pack | 0–5 °C | Non hazardous | Melts into water | Fresh produce, short haul deliveries | Provides moderate refrigeration but cannot keep fish frozen |
| Phase Change Material (PCM) | –20 °C to –70 °C | Often non hazardous | Usually no residue | Biologics requiring strict 2–8 °C or –20 °C ranges | Offers narrow band temperature control but does not reach dry ice cold |
Practical meaning: The table shows that disposable dry ice blocks for fish achieve much lower temperatures than gel packs or PCMs. They provide moisture free cooling and are essential when you need to keep fish frozen for extended periods. However, because dry ice is classified as hazardous, packaging must comply with UN 1845 labeling and weight limits.
Why Does Dry Ice Sublimate Instead of Melt?
Dry ice sublimates because CO₂ lacks a liquid phase at normal atmospheric pressure. When exposed to air, the solid CO₂ absorbs heat and turns directly into gas. Each kilogram absorbs about 571 kJ of heat during sublimation. This high latent heat makes disposable dry ice blocks extremely efficient at pulling heat away from fish. Since no liquid forms, there is no water residue; this prevents cross contamination and keeps fish texture intact.
Why Choose a Disposable Dry Ice Block for Fish?
Disposable dry ice blocks offer extended cooling, no residue, compact size and reusability, making them ideal for fish shipping. Here’s why you should consider them over traditional ice or gel packs:
Extended Cooling Duration
Dry ice remains effective for 24–48 hours and sometimes up to 72 hours depending on block size and insulation. Because sublimation is slower than melting, the cooling lasts longer than water ice or gel packs. This is crucial when shipping fish across long distances or through warm climates.
No Liquid Residue or Contamination
Regular ice melts and can create puddles that soak into fish packaging. Dry ice sublimates entirely, leaving no water or slime. This keeps packaging clean and reduces the risk of bacterial growth. It also eliminates the need for absorbent pads or drainage holes.
Compact and Lightweight
Disposable dry ice blocks are denser and more compact than water ice. A single block can replace multiple gel packs, saving space in the cooler. Reduced volume means more fish per container and lower shipping costs.
Cost Efficiency and Reuse Options
Although dry ice must be replenished for each shipment, some blocks are designed to be reusable. Reusing blocks reduces long term costs and waste. Additionally, the high cooling capacity relative to weight lowers the amount of material needed, which may decrease shipping expenses.
Enhanced Product Quality
By maintaining ultra low temperatures, dry ice preserves the taste, texture and nutritional value of fish. It prevents thaw–freeze cycles, limiting drip loss and maintaining color. Since it drives out oxygen, it also reduces oxidation and microbial growth.
Versatility Across Fish Types
A disposable dry ice block for fish works for fresh, frozen and processed fish:
Fresh fish: The block keeps temperatures just above freezing to maintain freshness and prevents spoilage.
Frozen fish: It maintains sub zero temperatures to prevent thawing.
Processed fish: Dry ice ensures smoked or prepared fish products stay at optimal temperatures, preserving quality.
How to Use Disposable Dry Ice Blocks for Fish Safely and Effectively
Using a disposable dry ice block for fish isn’t complicated, but you must follow best practices. Safe handling protects workers, preserves fish quality, and ensures regulatory compliance.
Step 1: Calculate Cooling Requirements
Estimate the amount of dry ice needed using the general guideline 5–10 pounds of dry ice per 15 quarts of cooler space for 24 hours. Adjust this amount based on shipment duration and ambient temperatures. For long shipments or high external temperatures, add more dry ice.
Step 2: Choose the Right Container
Select an insulated box made from expanded polystyrene (EPS) or polyurethane foam. The container should provide high thermal resistance and be sealed yet vented. Venting prevents pressure build up as CO₂ gas escapes. Avoid airtight containers.
Step 3: Pack Using a Layering Technique
Proper layering ensures even cooling:
Bottom layer: Place an insulating material like foam or cardboard at the bottom to prevent direct contact between the dry ice and the box.
Middle layer: Arrange fish evenly, leaving space for air circulation.
Top layer: Position the disposable dry ice block above the fish to create a “cold dome” that sinks cold air onto the products.
Fill void spaces: Use crumpled paper or extra insulation to reduce empty spaces and minimize thermal leakage.
Step 4: Provide Proper Ventilation
Leave small holes or vents in the container lid so CO₂ gas can escape. Without venting, pressure can build up, potentially damaging the package or posing a safety risk.
Step 5: Follow Safety Regulations
Dry ice is a Class 9 hazardous material and must be labeled as “carbon dioxide, solid” or “dry ice” with the UN number 1845 and the net weight. Airlines typically limit each package to 5.5 lbs (2.5 kg) of dry ice. Handlers should wear insulated gloves and goggles to prevent frostbite.
Step 6: Disposal and End of Use
Allow unused dry ice to sublimate in a well ventilated area away from people and animals. Never dispose of dry ice in sinks, drains or trash bins, as rapid gas release can cause damage. For re usable blocks, follow manufacturer instructions for cleaning and storage.
Tip Box: Sizing Disposable Dry Ice Blocks
| Transit Duration | Recommended Block Thickness | Approximate Dry Ice Weight per kg of Fish | Practical Meaning |
| Up to 24 hours | 12 mm sheet or thin block | 1 kg dry ice per 1 kg fish | Suits overnight shipments; keeps fish below –20 °C for one day |
| 24–48 hours | 18 mm sheet or thicker block | 1–1.5 kg dry ice per 1 kg fish | Ideal for two day deliveries or international flights |
| 48–72 hours | 24 mm sheet or multi layer block | 2 kg dry ice per 1 kg fish | Supports long journeys; multiple layers maintain –75 °C for 3 days |
Practical meaning: Selecting the right thickness ensures that the disposable dry ice block for fish provides sufficient cooling without overspending. Matching dry ice weight to product weight (1 : 1 ratio) and choosing appropriate thickness based on transit time are key factors.
Additional Safety and Packing Tips
Do not touch bare dry ice: Use gloves to avoid frostbite.
Never place dry ice directly on fish skin: Use a barrier to prevent localized freezing.
Pre chill your product: Frozen fish should be pre frozen to reduce the thermal load.
Use vented containers: Gas buildup can cause packages to burst.
Label packages clearly: Include hazard labels and weight information.
Real world case: A meal kit company switched from rigid dry ice blocks to flexible dry ice sheets. By wrapping each parcel with a 12 mm sheet and adding an insulated liner, the company reduced dry ice usage by 20 % and maintained –18 °C for 48 hours.
Environmental and Regulatory Considerations
Challenges of Polystyrene (EPS) Boxes
Traditional fish shipments often rely on expanded polystyrene (EPS) boxes due to their high insulation and low weight. However, 45–50 % of EPS fish boxes end up in landfill because contaminated polystyrene is difficult to recycle. EPS is made from fossil plastic that does not biodegrade; it disintegrates into microplastics that harm marine life. Many countries lack recycling infrastructure, and disposal costs are high. European regulations are tightening; the Single Use Plastics Directive bans some EPS containers, and many countries are imposing restrictions or bans on polystyrene packaging.
Sustainable Alternatives to EPS
Fiber boxes: New fiber cast boxes made from wood or agricultural fibers provide insulation comparable to EPS. They use renewable raw materials, have water repellent coatings and are robust and stackable. Fiber boxes can be folded flat, reducing waste volume by up to seven times and cutting disposal costs by up to 60 %. They also lower CO₂ emissions across the supply chain and can be recycled or composted.
Reusable insulated shipping containers (RISC): Durable boxes made from plastics or metal reduce single use waste. They are ideal for large shipments and can be returned and reused multiple times.
Biodegradable and compostable materials: Films made from PLA, pulp or chitosan offer eco friendly alternatives and have antimicrobial properties. Norway’s Leroy Seafood Group replaced 60 % of its EPS trays with recyclable PET and pulp trays, saving over 200 tonnes of plastic annually.
Edible and water soluble films: Seaweed based films dissolve in water and leave no waste. They are still in early stages but show promise for small fish portions.
Regulatory and Consumer Drivers
Hazardous materials rules: Dry ice shipments must comply with IATA, DOT and UN regulations.
Extended Producer Responsibility (EPR): Many countries are introducing regulations requiring producers to take responsibility for packaging waste.
Consumer preferences: Surveys show 54 % of U.S. consumers bought products with sustainable packaging in 2025 and 90 % are more likely to choose brands using eco friendly packaging.
Alternatives and Hybrid Cooling Solutions
Phase Change Materials (PCMs)
PCMs are materials that absorb or release heat at defined temperatures. They maintain narrow temperature ranges, such as 2–8 °C or –20 °C, making them suitable for chilled fish but not for deep frozen shipments. PCMs are reusable and typically non hazardous, which simplifies compliance. However, they cannot reach the ultra cold temperatures of dry ice and thus may not keep fish fully frozen.
Hybrid Systems
Combining disposable dry ice blocks with PCMs or gel packs provides longer cooling while reducing dry ice consumption. A hybrid system places PCMs around the fish to maintain moderate temperatures, with dry ice blocks on top for ultra cold conditions. This approach extends cooling duration and mitigates fluctuations. Real time sensors can monitor internal temperatures and alert operators if conditions deviate.
Water Ice and Gel Packs
Gel packs are cheaper and non hazardous but only maintain 0–5 °C for 6–12 hours. They are useful for short deliveries or live seafood but cannot keep fish frozen. Water ice is even less suitable for frozen fish because it melts and can damage packaging.
Reusable Insulated Containers
While not a cooling medium, reusable containers like Rotomolded coolers or vacuum insulated panels (VIP) enhance performance of any refrigerant. They reduce the amount of dry ice needed and limit external heat transfer.
2025 Trends: Innovations Shaping Disposable Dry Ice Blocks for Fish
Sustainability Initiatives
Businesses are developing biodegradable dry ice blocks and carbon capture production processes to reduce the environmental impact of CO₂. Manufacturers are experimenting with renewable energy sources for dry ice production and recycled CO₂ feedstocks.
Smart Monitoring and IoT Integration
New disposable dry ice blocks for fish are being paired with real time temperature sensors. These IoT devices provide live temperature data and alerts if the shipment warms up. Combined with GPS, they allow supply chain managers to track shipments and intervene before spoilage occurs.
Hybrid Cooling Systems
Hybrid solutions that blend dry ice blocks with PCMs or gel packs are becoming mainstream. By using both types of refrigerants, companies extend cooling durations, reduce dry ice usage and achieve smoother temperature profiles.
Sustainable Packaging Momentum
Fish exporters are switching from EPS to fiber boxes, paper based linings and reusable insulated containers. These sustainable materials reduce plastic pollution, lower CO₂ emissions and appeal to environmentally conscious consumers.
Market Growth and Investments
The global cold chain logistics market is expanding rapidly; research estimates the market will grow from USD 436.3 billion in 2025 to USD 1.36 trillion by 2034 (source: Precedence Research). Within this context, the dry ice market is projected to reach USD 1.67 billion in 2025 with a compound annual growth rate around 7.6 % (source: Coherent Market Insights). Investments in localized dry ice production hubs are rising due to supply disruptions, making dry ice more accessible for seafood businesses.
Policy and Consumer Pressure
As countries implement single use plastic bans and EPR programs, demand for eco friendly cold chain solutions is increasing. Consumers expect transparent sustainability practices, and businesses that adopt sustainable packaging gain competitive advantages.
Frequently Asked Questions
Q1: How long does a disposable dry ice block keep fish frozen?
A properly sized dry ice block can keep fish frozen for 24–48 hours, depending on block thickness, insulation and ambient temperature. Thicker blocks or multiple layers can extend cooling to 72 hours.
Q2: Can I use a disposable dry ice block for live fish?
No. Dry ice temperatures are far too cold for live seafood. For live fish, use gel packs or water ice to maintain chilled conditions around 0 °C to 5 °C.
Q3: What safety precautions should I take when handling disposable dry ice blocks?
Wear insulated gloves and goggles to protect skin and eyes. Never seal dry ice in an airtight container – venting is essential. Comply with hazard labeling and weight restrictions.
Q4: How should I dispose of a disposable dry ice block after shipping fish?
Allow the dry ice to sublimate in a well ventilated area, away from people or animals. Do not discard it in sinks or trash bins..
Q5: Are there eco friendly alternatives to disposable dry ice blocks for fish shipping?
Yes. Alternatives include PCMs for chilled shipments, reusable insulated containers and fiber cast boxes made from renewable materials. Biodegradable and compostable films are also being developed.
Summary and Recommendations
Key takeaways:
Disposable dry ice block for fish is an effective solution for shipping frozen seafood. It maintains extremely low temperatures (–78.5 °C) and prevents moisture contamination, offering extended cooling up to 48 hours. Proper packaging, ventilation and sizing are essential. Regulations classify dry ice as a hazardous material, so packages must be labeled and vented. Sustainable alternatives such as fiber boxes and biodegradable films are gaining traction due to environmental and regulatory pressures.
Next steps:
Assess your shipping needs: Determine whether your fish requires freezing or chilling.
Select the right disposable dry ice block: Choose block thickness based on transit time and product weight (1 : 1 ratio).
Optimize your packaging: Use insulated containers with proper venting and apply layering techniques.
Follow safety protocols: Wear protective gear, label packages and comply with weight limits.
Explore sustainable options: Investigate fiber boxes and hybrid systems to reduce environmental impact and prepare for future regulations.
About Tempk
Tempk is a global leader in cold chain logistics solutions, delivering high performance dry ice packs, insulated packaging and smart monitoring systems for seafood, pharmaceuticals and food delivery. Our innovations are designed to meet stringent shipping requirements, provide reliable temperature control and reduce environmental impact. We develop eco friendly products, including reusable and biodegradable dry ice packs, to help businesses meet regulatory standards and achieve sustainability goals.
Need expert guidance? Contact us for a consultation on choosing the right disposable dry ice block for fish and explore our range of cold chain solutions tailored to your business needs.
