Carbon monoxide (CO) is a toxic gas, but it’s also widely used as a tool in industry, research, and even medicine.

What is carbon monoxide used for?

1. Chemical manufacturing

Carbon monoxide is a key building block in industrial chemistry.

  • Used to make methanol, which then goes into fuels, plastics, paints, and solvents.
  • Used in “carbonylation” reactions to produce acetic acid for adhesives, textiles, and coatings.
  • Combined with hydrogen (synthesis gas) in the Fischer–Tropsch process to make liquid fuels and other hydrocarbons.
  • Acts as a reagent in many organic syntheses in the fine‑chemicals and pharmaceutical industries.

2. Metallurgy and materials

CO is important in metal production and treatment.

  • Used as a strong reducing agent to extract iron from iron ore in blast furnaces during steelmaking.
  • Helps remove metal oxides and rust from surfaces, improving metal purity and finish.
  • Used in some high‑temperature processes and as part of controlled atmospheres for heat treatment of metals.

3. Food and packaging

In very controlled, low concentrations, CO is used in the food industry.

  • Used in modified atmosphere packaging (MAP) for meat and fish to stabilize the bright red color of myoglobin (carboxymyoglobin formation), making products look fresh longer.
  • Sometimes used in specific food and beverage processes and formulations where CO‑containing gas mixtures help control acidity or processing conditions.

Even in food uses, CO is tightly regulated and applied under strict safety and labeling rules.

4. Medical and biological uses (research stage)

Despite its reputation, CO also has experimental medical roles.

  • At very low, controlled doses, CO shows anti‑inflammatory and tissue‑protective effects in animal and early human studies (e.g., organ transplantation, ischemia–reperfusion injury).
  • Being tested as part of “CO‑releasing molecules” (CORMs) as potential drugs for inflammatory and cardiovascular conditions.
  • Used diagnostically in lung diffusion capacity tests, where a tiny dose of CO helps measure how well gases move from the lungs into the blood.
  • Exhaled CO measurement helps monitor smoking status and some respiratory problems.

5. Environmental monitoring and energy tech

CO also matters in environmental science and advanced technologies.

  • Monitored as a key air pollutant to assess incomplete combustion and indoor/outdoor air quality.
  • Used as a tracer in atmospheric chemistry and climate studies because it reacts with hydroxyl radicals and influences methane lifetime.
  • Plays a role in some carbon capture and utilization schemes, where CO₂ is turned into CO and then into useful chemicals.
  • Can serve as a fuel in certain high‑temperature fuel cells (like solid oxide fuel cells) for electricity generation.

6. Everyday / indirect situations

Most people “use” CO only indirectly—and must stay safe around it.

  • It appears as a by‑product of burning fuels (cars, heaters, generators, stoves, fireplaces) when combustion is incomplete.
  • This is not a purposeful use but a hazard; CO binds to hemoglobin much more strongly than oxygen and can cause poisoning and death.
  • Because of that, CO detectors and strict ventilation rules are standard in homes, workplaces, and garages.

Mini story to tie it together

Imagine a steel plant: carbon monoxide produced in the furnace helps strip oxygen from iron ore so molten iron can be made into beams for buildings. Nearby, a chemical plant uses purified CO to make methanol and acetic acid that end up in paints and plastics. Downstream, a meat‑packing facility uses tiny, controlled amounts of CO in packaging to keep steaks looking fresh on supermarket shelves—while CO alarms on the wall silently watch for any dangerous leaks.

TL;DR: Carbon monoxide is mainly used as a chemical building block, a reducing agent in metal production, a controlled component in food packaging, a tool in medical diagnostics and experimental therapies, and a target for environmental monitoring—but because it is highly toxic, all intentional uses rely on strict safety controls.

Information gathered from public forums or data available on the internet and portrayed here.