Is Your Goose Cooked? The Potential Health Impacts of CO2 Pipeline Ruptures

Is Your Goose Cooked? The Potential Health Impacts of CO2 Pipeline Ruptures

Author: Paul Blackburn, Bold Alliance
Sept. 25, 2024

Introduction

This is the second of a four-part blog series about carbon dioxide (CO2) pipeline ruptures. It focuses on the potential health impacts of CO2 pipeline ruptures. The other blogs in this series cover:

• 1: Chasing a Wild Goose Egg: Understanding Computer Plume Modeling for Carbon Dioxide Pipeline Ruptures (The basics of CO2 pipeline ruptures and the need to know the danger zone following a rupture – Sept. 23, 2024)
• 2: Is Your Goose Cooked? The Potential Health Impacts of CO2 Pipeline Ruptures (Sept. 25, 2024)
• 3: A Tale of Perfect Goose Eggs: CO2 Plume Computer Modeling Options (The computer models available to predict the size of danger zones for CO2 pipeline ruptures – Sept. 30, 2024)
• 4: Good for the Goose, Good for the Gander: Who Should Have Access to Plume Modeling for CO2 Pipeline Ruptures? (Public access to CO2 pipeline rupture computer modeling and industry and government efforts to keep it secret – Oct. 2, 2024) 

The goal of this series is to help current and potential future neighbors of CO2 pipelines access technology that can help them understand whether or not they are at risk.  Much thanks to Dr. Kathleen Campbell for this joint writing collaboration on health issues.  

What Are the Possible Health Effects of CO2 Pipeline Ruptures?

The effect of CO2 exposure on different individuals depends on a variety of factors, including CO2 concentration, the duration of exposure, and a victim’s preexisting medical conditions.  At the same CO2 concentration over the same period of time, some people may remain conscious while others may not.  At high concentrations, CO2 gas can immediately disable and then kill within minutes – your goose would be cooked.  At moderate concentrations, CO2 gas can cause unconsciousness and seizures.  At relatively low concentrations, CO2 can still intoxicate and cause confusion and hearing and vision loss, which could result in injuries or even fatalities for those who are, for example, driving, using dangerous machinery, or outside in dangerous weather conditions.  Below is a table of health effects from the USEPA.  There are many similar tables from the government, industry, scientific, and commercial sources.  

The symptoms listed above are readily measured in observational studies but may not include all health impacts.  Moreover, CO2 exposures may be more serious than the above chart indicates, particularly for vulnerable populations such as those with asthma and other respiratory diseases.

The CDC and EPA CO2 exposure standards were typically established for young to middle-aged healthy individuals based on data gathered in studies using volunteers.  Volunteers with preexisting medical conditions were probably excluded from these studies.  In contrast, communities along pipelines include seniors, children, handicapped individuals, and individuals with a wide array of medical conditions.  Any respiratory condition could greatly exacerbate the impacts of CO2 exposure.  Even being home with a respiratory infection such as COVID could increase susceptibility.  Similarly, anyone with a cardiovascular or neurologic disorder could be at elevated risk.  We also know from the Satartia rupture that exposure to high concentrations of CO2 can have long-term health effects.  

The CDC advises against pregnant women being exposed to elevated CO2 levels.  Based on animal studies, CO2 may cause birth defects including blindness and vertebral malformations.  The CDC and the USDA specify in their guidelines that pregnant women should consult with their physicians and supervisors before exposure to elevated CO2 levels. 

With regard to the risk of death from CO2 exposure, the following table is from a paper entitled, Assessment of the Major Hazard Potential of Carbon Dioxide (CO2).  It identifies CO2 concentrations that cause a 1-5% risk of fatality (called the specified level of toxicity, or SLOT), and also CO2 levels at which there is 50/50 risk of death (called the significant likelihood of death, or SLOD).  

This data indicates that even relatively moderate concentration of CO2 (6.3%) may cause death for exposures of an hour or longer, and that CO2 concentrations not even twice as high (8.4%) would be expected to kill half of all exposed persons.  As shown by this table, the risk of death depends on CO2 concentration and duration of exposure, but it also depends on whether or not a person has medical conditions that increase vulnerability.  

The CO2 pipeline industry likes to claim that the CO2 released from a rupture of a CO2 pipeline would not be any more dangerous than the fizz in your soda.  The foregoing scientific evidence show that this claim is untrue.  While it is true that low concentrations of CO2 are not dangerous, it is also true that high concentrations of CO2 can cause serious health impacts and even death.  Water, similarly, is not toxic, but you can still drown in it.  

What Are the Government Standards for Human Exposure?

The federal Center for Disease Control’s (CDC) National Institute for Occupational Safety and Health (NIOSH) Pocket Guide to Chemical Hazards and the  American Petroleum Institute’s (API) Carbon Dioxide (CO2) Emergency Response Tactical Guidance Document contain three concentration standards.  For longer daily exposures, the applicable government standard is called the Permissible Exposure Limit (PEL) is 5,000 ppm (0.5%), which is the maximum allowable exposure allowed over an 8-hour work shift on a daily basis, but only if the Short-Term Exposure Limit (see below) is not met or exceeded at any time during those 8 hours.  According to the API’s Tactical Guidance Document, workers may be repeatedly exposed over a conventional eight-hour workday and a 40-hour workweek, day after day, to a concentration of up to 5,000 ppm (0.5%) CO2 without adverse effect.  This means that exposures above this level may have health effects.

The CDC has also established a Short-Term Exposure Limit (STEL) of 30,000 ppm (3%) CO2 for no more than 15 minutes.  According to the API’s Tactical Guidance Document, people exposed to 30,000 ppm (3%) CO2 must be evacuated within 15 minutes.  The API Tactical Guidance Document states: “The TLV-STEL is the concentration to which it is believed that workers can be exposed continuously for a short period of time without suffering from 1) irritation, 2) chronic or irreversible tissue damage, 3) dose-rate-dependent toxic effects, or 4) narcosis of sufficient degree to increase the likelihood of accidental injury, impaired self-rescue, or materially reduced work efficiency.”  Put another way, CO2 concentrations of 3% for longer than 15 minutes can cause physical irritation, tissue damage, toxic effects, and make self-rescue difficult.  The API Tactical Guidance Document states that workers, such as first responders, required to work in CO2 concentrations in this range or higher for longer than 15 minutes must be provided with self-contained breathing apparatus (an air tank).  

The CDC designates 40,000 ppm (4%) CO2 as the concentration that is “Immediately Dangerous to Life and Health” (IDLH).  The CDC Guidelines are clear.  “Immediately Dangerous to Life or Health” means exactly that; there is no minimum exposure duration for that designation.  A 40,000 ppm (4%) CO2 concentration level is not an allowable exposure level for any duration of exposure.  All workers exposed to 4% or higher CO2 concentrations for any length of time must be provided with self-contained breathing apparatus. 

These guidelines are consistent across multiple government agencies. The USDA’s Carbon Dioxide Health Hazard Information Sheet likewise designates 40,000 ppm (4%) as Immediately Dangerous to Life or Health, and also recognizes that at 80,000 ppm (8%) symptoms include dimmed sight, sweating, tremor, unconsciousness, and possible death. Further, the USDA recommends that no one be allowed to enter an area with 20,000 ppm (2%) until it is ventilated to reduce CO2 levels.  

After the rupture of a large-diameter CO2 pipeline, CO2 concentrations within approximately 1,000 feet or more of the rupture, depending on pipeline diameter and length, may rise to very dangerous levels in less than 5 minutes.  Even a mile or more away, depending on pipeline diameter, wind direction, etc., CO2 concentrations may rise to dangerous levels in less than 15 minutes.  For example, the first seizure in Satartia was reported 17 minutes after and approximately one mile away from the rupture.  Thus, when a CO2 pipeline ruptures, nearby persons may not have enough time to self-evacuate or be rescued by first responders, even if they are exposed to just the 30,000 ppm (3%) level, and even if they are immediately notified when a rupture occurs, assuming it is immediately detected.

It is beyond dispute that CO2 pipeline rupture may release CO2 in amounts that are deadly, or at least dangerous to your health, depending on the amount of CO2 released and your distance from the rupture site.  If you found this blog helpful and would like to know more about the types of plume models available to estimate CO2 pipeline rupture danger zones, consider reading the next blog in the series.

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