Our Atmosphere

CO2 removal is a necessity

By mid century, we’ll need to remove billions of tons each year – equivalent to 10-20% of today’s annual global emissions – if we want to keep global temperature rise below 1.5°C. Even if emissions stopped tomorrow, the CO2 that’s already in the atmosphere will take thousands of years to dissipate – all the while the planet will continue to warm. We need to permanently remove CO2 from the atmosphere, and Direct Air Capture is the best solution available to do this today.
mineral photo

Our process

Designed for scale, engineered for impact

We use limestone, one of the world’s most abundant and inexpensive minerals, to capture CO2 directly from the atmosphere, and then permanently and safely store the CO2 underground or in materials like concrete.

How our Direct Air Capture system works

Using limestone like a sponge

Limestone is made up of calcium oxide and CO2. When CO2 is removed from limestone, the remaining calcium oxide acts like a sponge – absorbing CO2 so it can return to its natural limestone state. Our technology accelerates this natural property of limestone, reducing the time it takes to absorb CO2 from years to just 3 days.

Removing CO2 from limestone

We heat limestone mineral powder in a renewable-energy powered kiln to remove the CO2. Our partners then permanently and safely sequester this CO2 in deep geological reservoirs, or in long-lasting materials like concrete.

Soaking up CO2 from the atmosphere

Once the CO2 is removed, we spread this mineral powder onto vertically-stacked trays and “treat” it to optimize its ability to uptake CO2 in different environmental conditions.

Repeating the process

Like repeatedly wringing a sponge, we loop this limestone mineral powder through our system to continuously suck CO2 from the atmosphere – a cyclic process that not only lowers costs but also reduces how much limestone must be mined.

Our Technical Advantage

The fastest path to low-cost Direct Air Capture

We will remove CO2 from the air at increasingly lower costs as our technology scales, allowing us to meaningfully impact the climate problem.

Low-cost inputs

Making up 4% of the Earth’s surface and costing as little as $10 a ton, limestone is more abundant, far less expensive, and easier to source than custom engineered materials.


Our carbon removal facilities are built for simple, mass manufacturing and have independent components and processes that can be optimized over time.

Learning from every ton

We constantly collect data to refine and optimize our CO2 uptake rate – further increasing our output and reducing cost.

Our facility

America’s first commercial DAC facility

In a world first for Direct Air Capture technology, our facility in Tracy, California, is capturing CO2 from the atmosphere which is then embedded permanently in concrete. Working with our partner CarbonCure, this CO2-enriched concrete is laid in the foundations of buildings and structures, with the added benefit of creating stronger concrete.

We’re also proud to be implementing a community governance model, which will gather stakeholder input on financial and programmatic investments into Tracy and San Joaquin County community organizations beginning in Q1 of 2024.
two people in blue helmets
photo of people working on facility
two hands in blue gloves
image: minerals

Your Impact

Take action on climate change with Heirloom

Help us permanently remove 1 billion tons of CO2 from our atmosphere by 2035.