Oxygen Toxicity Explained: Risks, Symptoms, & Safety

When you use oxygen therapy to treat a respiratory illness, you must be aware of the side effects of too much oxygen. Breathing in too much supplemental oxygen, referred to as oxygen toxicity can occur whether you use an oxygen concentrator or oxygen tank. Know the signs and symptoms and what to do if you take too much oxygen.

What Is Oxygen Toxicity?

Oxygen toxicity occurs when people are ingesting too much oxygen into their system, causing a cough, trouble breathing, or even lung damage. As you breathe, oxygen from the air enters your lungs and saturates into your blood. The oxygen then goes to all parts of the body through the blood. It keeps organs and tissues functioning normally. But, too high a level of oxygen can harm lung tissues. Your oxygen level should not go above 110 mmHg. A normal, healthy blood oxygen level should be between 95 and 100 percent. When that level is pushed up above the threshold, you’re getting too much oxygen in the bloodstream and may experience oxygen toxicity.

Oxygen Toxicity Symptoms

While using supplemental oxygen to treat a respiratory illness, you can always look for these symptoms of oxygen toxicity:

• Mild throat irritation
• Coughing
• Chest pain
• Difficulty breathing even while using supplemental oxygen
• Minor muscle spasms in the face and hands
• Dizziness
• Blurred vision
• Nausea and feelings of uneasiness
• In severe cases confusion and seizures

Identifying these symptoms early helps prevent serious damage from oxygen toxicity. Speak to your doctor about your oxygen therapy prescription to ensure you never exceed healthy oxygen levels. Adhering to guidelines established by your doctor for supplemental oxygen use helps prevent oxygen toxicity from ever happening.

How Can Oxygen Be Toxic?

While oxygen gives life, it can also damage it. Too much oxygen actually reduces lung capacity and ends up slowing down the delivery of oxygen to your body's tissues. Also, certain tissues are sensitive to oxygen, making them susceptible to damage if they absorb too much. The lining of the lungs and the walls of the arteries are all oxygen-sensitive tissues.

Anyone using an oxygen concentrator or oxygen tank can easily overdose on pure oxygen if they are not careful or do not follow their doctor’s recommendations for oxygen use. Relying on oxygen can also make individuals more likely to overdo use as they become accustomed to the effects of pure oxygen.

Can You Get Too Much Oxygen?

Excesses of pure oxygen are not limited to patients using supplemental oxygen. Oxygen toxicity can affect scuba divers who depend on oxygen tanks to stay submerged for periods of time and may take in too much oxygen during a dive. Some patients who are using ventilators to breathe also may experience oxygen toxicity, even while they are in a hospital. Hospital staff members pay close attention to patients on ventilators. Hyperbaric oxygen therapy also comes with a risk factor for oxygen toxicity.

Patients using supplemental oxygen at home are more at risk of oxygen toxicity as their daily use is not monitored by health professionals.

What Happens When COPD Patients Receive Too Much Oxygen?

COPD patients using oxygen therapy can experience hypercapnia (partial pressure of carbon dioxide in arterial blood greater than 45 mm Hg). That’s why it is critical for COPD patients to take all necessary precautions to prevent the overuse of oxygen.

COPD patients tend to use supplemental oxygen on a daily basis, making them more susceptible to overuse. Knowing the symptoms of oxygen toxicity and responding to those symptoms immediately is the best way for COPD patients to prevent oxygen toxicity or stop it before it gets worse. They may experience headaches, drowsiness, and difficulty breathing as a result of oxygen toxicity.

How to Treat Oxygen Toxicity

If you experience oxygen toxicity, the first step is to stop oxygen therapy. Allow your lungs to recover. Secondly, peak to your doctor to ensure your toxicity level is not dangerous.

Preventing oxygen toxicity just requires awareness. Patients can measure blood oxygen levels to ensure they are treating their illness within safe guidelines. Blood oxygen levels can be measured using a pulse oximeter. This non-invasive device can be used at home to determine if your blood oxygen saturation has reached a tipping point toward oxygen toxicity. When you use supplemental oxygen regularly, rely on this simple gauge to help you measure and maintain healthy oxygen levels.

Can Too Much Oxygen Kill You?

In a recent study, researchers found that oxygen therapy increases the risk of death when given liberally to patients with acute illnesses, such as heart attack, stroke, and trauma.¹ Doctors are taking extra precautions in hospitals and when prescribing oxygen therapy at home to make supplemental oxygen a safe and healthy treatment. Continuous monitoring of blood oxygen levels helps ensure oxygen therapy that helps rather than harms.

For most patients, the symptoms of oxygen toxicity leave you feeling sick enough to not continue your oxygen therapy. If you do not have a serious illness, then recovering from the effects of too much oxygen will be your only concern.

Where Can I Buy Equipment for Oxygen Therapy at Home?

You can find oxygen concentrators and accessories at most medical equipment retailers, including The Oxygen Concentrator Supplies Shop located in West Berlin, New Jersey. You can also shop online for all your oxygen concentrator needs. Find both home and portable oxygen concentrators at The Oxygen Concentrator Supplies Shop. Speak to our knowledgeable staff to help you select the best oxygen concentrator based on your prescription by calling 888-941-1688.

This post was updated with the latest information in March 2026.

Oxygen toxicity occurs when you breathe oxygen at a higher partial pressure than your body is designed to handle. This creates an overabundance of "free radicals"—unstable molecules that damage cell membranes and disrupt DNA.

When you use oxygen therapy to treat a respiratory illness, you must be aware of the side effects of too much oxygen. Breathing in too much supplemental oxygen, referred to as oxygen toxicity can occur whether you use an oxygen concentrator or oxygen tank. Know the signs and symptoms and what to do if you take too much oxygen.

Oxygen toxicity occurs when people are ingesting too much oxygen into their system, causing a cough, trouble breathing, or even lung damage. As you breathe, oxygen from the air enters your lungs and saturates into your blood. The oxygen then goes to all parts of the body through the blood. It keeps organs and tissues functioning normally. But, too high a level of oxygen can harm lung tissues. Your oxygen level should not go above 110 mmHg. A normal, healthy blood oxygen level should be between 95 and 100 percent. When that level is pushed up above the threshold, you’re getting too much oxygen in the bloodstream and may experience oxygen toxicity.

If you are using a home or portable oxygen concentrator and suspect your levels are too high, look for these specific physical warning signs:

1. Early Signs: Mild throat irritation, a persistent dry cough, and a "burning" sensation in the chest or under the breastbone.

2. Neurological Changes: Sudden dizziness, blurred vision, or ringing in the ears (tinnitus).

3. Physical Twitches: Minor muscle spasms or tremors, particularly in the face or hands.

4. Respiratory Distress: Feeling short of breath or "air hungry" even though you are receiving supplemental oxygen.

5. Advanced Symptoms: Nausea, mental confusion, or extreme drowsiness (lethargy).

What to do: If you experience these symptoms, do not adjust your equipment settings yourself. Contact your healthcare provider immediately to verify your prescribed Flow Rate (LPM).

Clinicians categorize oxygen toxicity into two distinct types based on which part of the body is under attack:

Central Nervous System (CNS) Toxicity

Mostly seen in deep-sea divers using Nitrox or Heliox, or patients in Hyperbaric Oxygen Therapy (HBOT).

• The Cause: Breathing high concentrations of $O_2$ at pressures greater than 1.6 atmospheres.

• Warning Signs: Visual changes (tunnel vision), ringing in the ears (tinnitus), nausea, and the most dangerous symptom: seizures.

Pulmonary (Lung) Toxicity

This is the version most relevant to medical patients on long-term supplemental oxygen.

• The Cause: Prolonged exposure (typically 24+ hours) to high concentrations of oxygen at normal atmospheric pressure.

• Warning Signs: A "burning" sensation under the breastbone, dry cough, and shortness of breath. If left unchecked, it can lead to pulmonary edema (fluid in the lungs).

For those using CPAP or BiLevel machines in 2026, the risk isn't usually the oxygen itself, but how it interacts with Chronic Obstructive Pulmonary Disease (COPD).

• The "Hypoxic Drive" Myth: In 2026, we know the danger for COPD patients isn't just "forgetting to breathe." It’s that too much oxygen causes the lungs to stop matching air to blood flow effectively

• The Result: This leads to Hypercapnia—a dangerous buildup of carbon dioxide in the blood because the body isn't prompted to exhale it efficiently.

Warning Signs of Oxygen Overload in COPD Patients

For patients with COPD, receiving too much oxygen can lead to carbon dioxide (CO2) retention, also known as hypercapnia. This is a medical emergency that presents differently than standard oxygen toxicity. Look for:

• Morning Headaches: A dull, throbbing headache upon waking.

• Extreme Somnolence: Being difficult to wake up or feeling "foggy" and excessively tired during the day.

• Flushed Skin: A red or warm appearance in the face or extremities.

• Tachypnea: Rapid, shallow breathing.

• Mental Confusion: Difficulty following conversations or sudden disorientation.

Can an Oxygen Machine Give You Too Much Oxygen?

Yes, it is possible to receive too much oxygen from a machine, but it is rarely due to a mechanical "malfunction." Oxygen toxicity from a machine typically occurs in two ways:

1. Incorrect Flow Rate: If the Liter Per Minute (LPM) setting on your concentrator is set higher than your doctor’s prescription.

2. Unauthorized Adjustments: Increasing your oxygen intake because you feel short of breath without consulting a pulse oximeter or a physician.

Safety Note: Oxygen concentrators are designed to deliver a specific concentration. They cannot "spike" in purity on their own. Toxicity is almost always a result of duration and flow rate rather than a machine error.

Can You Die From Oxygen Toxicity?

Yes, oxygen toxicity can be fatal, but it is extremely rare in home-care settings. Death from oxygen toxicity generally occurs under two specific conditions:

• Central Nervous System (CNS) Toxicity: Typically occurs in deep-sea diving or hyperbaric chambers, leading to seizures and immediate respiratory failure.

• Pulmonary Toxicity: Occurs in clinical settings (like ICUs) where a patient is breathing 100% oxygen for more than 24 hours, leading to irreversible lung scarring (fibrosis) and fluid buildup.

For home users, the risk of death is low because most home concentrators deliver lower concentrations than clinical ventilators. However, untreated CO2 retention in COPD patients is the primary fatal risk associated with improper oxygen use at home.

If you are using supplemental oxygen with your CPAP:

1. Follow the Flow Rate: Never increase your liters-per-minute (LPM) without a doctor's order.

2. Monitor Your SpO2: Use a high-resolution oximeter that syncs with your CPAP data (like SleepHQ) to ensure your levels are stable, not excessive.

3. Check Your Equipment: Ensure your oxygen "bleed-in" adapter is placed after the machine but before the heated tubing to ensure proper mixing.

How to Treat and Recover from Oxygen Toxicity

If you or a loved one are showing signs of oxygen overload, follow these steps:

1. Immediate Action: Reduce or stop the supplemental oxygen only if you can maintain safe saturation levels (90-92%) and call your doctor immediately.

2. Medical Evaluation: A doctor may perform an Arterial Blood Gas (ABG) test to check for CO2 levels and oxygen partial pressure.

3. Pressure Reduction: In clinical cases, treatment involves lowering the "Fraction of Inspired Oxygen" (FiO2) to the lowest level that maintains adequate tissue oxygenation.

4. Recovery Time: Most mild cases of pulmonary oxygen toxicity (coughing/chest pain) resolve within 24 to 48 hours once oxygen levels are normalized.

5. Antioxidant Support: In some hospital settings, doctors may use specific protocols to reduce the "free radical" damage caused by the excess oxygen.

You can find oxygen concentrators and accessories at The CPAP Shop located in West Berlin, New Jersey. You can also shop online for all your oxygen concentrator needs. Find both home and portable oxygen concentrators at The CPAP Shop. Speak to our knowledgeable staff to help you select the best oxygen concentrator based on your prescription by calling 866-414-9700.