Category Archives: Toxic Gases

Environmental pollution, Lithium Pollution, Pollution, SO2, Toxic Gases

Toxic gases released during the burning of Lithium-ion batteries (SO2)

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The third toxic gas I will be discussing is sulfur dioxide (SO2), a colourless but odorous gas that is highly toxic (United States Environmental Protection Agency, 2023). It is most commonly produced from the burning of fossil fuels and by the smelting of sulfur-containing mineral ores (Queensland Government, 2017). Naturally, erupting volcanoes are a significant source of SO2 emissions (Queensland Government, 2017). Similar to HF discussed in blog 11, SO2 is much more toxic compared to other gases released during the burning of lithium-ion batteries (LIBs) (Peng et al., 2020). 

Within batteries, SO2 is produced from burning sulfur-based compounds which are commonly used as reduction-type additives (Peng et al., 2020; Zhang, 2006). Similar to other toxic gases released during the burning of LIBs, the concentration of SO2 released depends on the state of charge (SOC) of the battery (Peng et al., 2020). The higher the SOC, the higher the concentration of SO2 released (Peng et al., 2020) (Figure 1). Despite, a lower concentration at lower SOCs, SO2 continues to make up a large part of all the toxic gases released regardless of SOC (Peng et al., 2020). While the maximum concentration of SO2 released, 115 mg/m3 (around 43.89 ppm), does not pose an immediate threat to the survival of a person, this concentration is more than enough to cause, mucositis, irritation to mucous membranes (Peng et al., 2020; Cleveland Clinic, 2022 ). 

According to Queensland Government (2017), the recommended air quality standards for sulfur dioxide are:

  • 0.20 ppm for a 1-hour exposure period
  • 0.08ppm for a 24-hour exposure period
  • 0.02ppm for an annual exposure period.

Health impacts of high concentrations of SO2:

  1. Respiratory problems
  • Difficulty to breath, people with existing respiratory problems such as asthma, and young children are particularly sensitive to the impacts of inhaling SO2. 
  • People with existing heart problems and diseases are also much more sensitive to the effects of SO2. 

2. Painful sores in the mouth/ gastrointestinal symptoms

  • High concentrations of SO2 will result in soreness in the mouth due to mucositis. Coughing and throat irritation are common symptoms related to high exposure to SO2 as well. 

(United States Environmental Protection Agency, 2023; Queensland Government, 2017)

Besides the direct impacts of SO2, SO2 can react with other chemicals in the atmosphere to form small particles that can easily enter the lungs of a person causing adverse health impacts (Queensland Government, 2017). For instance, reactions between SO2 and NOx form sulfates, which form fine particles (He et al., 2015). These fine particles are often the main culprit behind haze in parts of the world (He et al., 2015). They were also the main cause of the major haze events in Beijing-Tianjin-Hebei regions in China in 2013 (He et al., 2015). 

Figure 1: Haze event in Beijing in 2013 (Branigan, 2013)

Reference List

Branigan, T. (2013, January 14). Beijing smog continues as Chinese state media urge more action. The Guardian. https://www.theguardian.com/world/2013/jan/14/beijing-smog-continues-media-action 

Cleveland Clinic. (2022). Mucositis: Types, Symptoms & Treatment. https://my.clevelandclinic.org/health/diseases/24181-mucositis#:~:text=Mucositis%20is%20inflammation%20of%20the,painful%20and%20carries%20certain%20risks 

He, H., Wang, X., Ma, Q., Ma, J., Chu, B., Ji, D., Tang, G., Liu, C., Zhang, H., & Hao, J. (2015). Mineral dust and NOx promote the conversion of SO2 to sulfate in heavy pollution days. Scientific Reports, 4(1). https://doi.org/10.1038/srep04172 

Peng, Y., Yang, L., Ju, X., Liao, B., Ye, K., Li, L., Cao, B., & Ni, Y. (2020). A comprehensive investigation on the thermal and toxic hazards of large format lithium-ion batteries with LiFePO4 cathode. Journal of Hazardous Materials, 381, 120916. https://doi.org/10.1016/j.jhazmat.2019.120916 

Queensland Government. (2017, March 27). Sulfur dioxide. Environment, Land and Water | Queensland Government. https://www.qld.gov.au/environment/management/monitoring/air/air-pollution/pollutants/sulfur-dioxide#:~:text=Sulfur%20dioxide%20affects%20the%20respiratory,as%20asthma%20and%20chronic%20bronchitis 

United States Environmental Protection Agency. (2023, February 16). Sulfur Dioxide Basics | US EPA. US EPA. https://www.epa.gov/so2-pollution/sulfur-dioxide-basics 

Zhang, S. (2006). A review on electrolyte additives for lithium-ion batteries. Journal of Power Sources, 162(2), 1379–1394. https://doi.org/10.1016/j.jpowsour.2006.07.074

CO and CO2, Electric Vehicles, Environmental pollution, Lithium-ion battery, Toxic gases

Toxic gases released during the burning of Lithium-ion batteries (CO and CO2)

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Similar to hydrogen fluoride (HF), carbon monoxide (CO) and carbon dioxide (CO2) are common toxic gases that are released in the burning of LIB (Peng et al., 2020 ). CO is one of the two asphyxiant gas in ISO 13571 (Peng et al., 2020). 

ISO 13571:2012 establishes procedures to evaluate the life-threatening components of fire hazard analysis in terms of the status of exposed human subjects at discrete time intervals. – (International Organization for Standardization, 2020)

What is an asphyxiant gas?

Asphyxiant gas is a gas that results in hypoxia, the decrease of oxygen level in body tissue (Cleveland Clinic, 2022), by disarranging oxygen in the respiratory system (Gold, 2022). Besides hypoxia, asphyxiant gases will also cause ischaemia and metabolic acidosis (Gold, 2022; Cowled, 2011). Ischaemia causes deficiencies in blood oxygen, glucose and other substances (Cowled, 2011). When the supply of blood is lower than the demand, the body is no longer able to support essential normal functions (Cowled, 2011). The decrease in blood oxygen and other key substances deranges metabolic function which plays a crucial role in converting food and water into energy in the body (Cowled, 2011; Schoeller & Fjeld, 1991). On the other hand, metabolic acidosis is the buildup of acid in the body when the kidney is unable to remove enough acid in time due to failure (Gold, 2022). 

Symptoms:

  • Headaches, vomiting, lethargy, confusion
  • Loss of appetite 
  • Chest pain
  • Shortness of breath 
  • Fast heart rate
  • Loss of consciousness
  • Cardiac arrest

(Gold, 2022)

The symptoms a person suffers from by inhaling CO vary according to the concentration of CO and the duration they are exposed to. Furthermore, the deleterious effects of CO can be amplified when CO2 is breathed in with CO (Peng et al., 2020). As both of these gases are produced in conjunction with the burning of batteries, the effects of CO will be intensified. 

According to CO2 Meter (2023), the duration before CO takes effect significantly reduces when the concentration of CO exceeds 200 ppm (Figure 1). 

Figure 1: Carbon monoxide levels chart (CO2 Meter, 2023)

Burning behaviours of a 68 Ah battery (Figure 2) was studied by Peng et al. (2020) at different state of charge (SOC) and the concentration of CO and CO2 released over time was studied (Figure 3). 

Figure 2: 68 Ah lithium iron phosphate battery (Peng et al., 2020)

Figure 3: Experimental setup (Peng et al., 2020)

Batteries at a higher SOC produced the maximum CO and CO2 in the shortest duration after the battery started burning (Peng et al., 2020) (Figure 4). CO production reached a maximum of 258 ppm for 100% SOC albeit for a very short duration (Peng et al., 2020). 

Figure 4: Graphs of CO and CO2 production (Peng et al., 2020)

Although this concentration of CO will not have immediate health impacts when exposed to such a short period of time (Figure 1), we must bear in mind that this experiment used a 68 Ah battery with a nominal voltage of 3.22 V (Peng et al., 2020). According to E.ON, (n.d.), the battery capacity of an electric car (EV) is around 40 kWh with some going as high as 100 kWh and the common voltage of the batteries are 280 V and 360 V (Matsusada Precision Inc., 2019). A battery with a capacity of  40 kWh and voltage of 280 V will have a current of 143 Ah, more than double the current of the battery used in the experiment. Burning this battery will most likely increase the concentration of CO and CO2 produced to a lethal concentration that is fatal within minutes of exposure (Figure 1). 

 

Reference List

Cleveland Clinic. (2022). Hypoxia: Causes, Symptoms, Tests, Diagnosis & Treatment. https://my.clevelandclinic.org/health/diseases/23063-hypoxia#:~:text=Hypoxia%20is%20low%20levels%20of,Hypoxia%20can%20be%20life%2Dthreatening 

CO2 Meter. (2023, January 23). Carbon Monoxide Levels Chart. https://www.co2meter.com/blogs/news/carbon-monoxide-levels-chart 

Cowled, P. (2011). Pathophysiology of Reperfusion Injury. Mechanisms of Vascular Disease – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK534267/#:~:text=Ischaemia%20occurs%20when%20the%20blood,begin%20during%20this%20ischaemic%20phase 

E.ON. (n.d.). Electric vehicles | Battery | Capacity and Lifespan. https://www.eonenergy.com/electric-vehicle-charging/costs-and-benefits/battery-capacity-and-lifespan.html#:~:text=The%20average%20capacity%20is%20around,higher%20the%20kWh%20the%20better 

Gold, A. (2022, September 26). EMS Asphyxiation And Other Gas And Fire Hazards. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK519487/ 

International Organization for Standardization. (2020). ISO 13571:2012. ISO. https://www.iso.org/standard/56172.html 

Matsusada Precision Inc. (2019, June 4). Power Supply and Voltage of EV Motor | Tech | Matsusada Precision. Matsusada Precision. https://www.matsusada.com/column/ev-power.html#:~:text=Lithium%2Dion%20batteries%20are%20the,connected%20in%20series%20and%20parallel 

Peng, Y., Yang, L., Ju, X., Liao, B., Ye, K., Li, L., Cao, B., & Ni, Y. (2020). A comprehensive investigation on the thermal and toxic hazards of large format lithium-ion batteries with LiFePO4 cathode. Journal of Hazardous Materials, 381, 120916. https://doi.org/10.1016/j.jhazmat.2019.120916 

Schoeller, D. A., & Fjeld, C. R. (1991). Human Energy Metabolism: What Have We Learned from the Doubly Labeled Water Method? Annual Review of Nutrition, 11(1), 355–373. https://doi.org/10.1146/annurev.nu.11.070191.002035 

Environmental pollution, HF, Pollution, Toxic Gases

Toxic gases released during the burning of Lithium-ion batteries (HF)

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The first gas that we will be discussing in detail is hydrogen fluoride (HF). HF is a colourless gas which readily dissolves in water to form hydrofluoric acid (HFA) (Marx et al., 2005; Gad & Sullivan, 2014). HF is an extremely toxic gas and HFA is one of the strongest existing acids (Marx et al., 2005). 

Ingestions of more than 20 mg/kg body weight are considered a lethal dose. – Marx et al., 2005

Adverse health impacts will arise when exposed to it either in gaseous or liquid form (Centers for Disease Control and Prevention, 2018). 

Immediate signs and symptoms of exposure to HF/HFA:

  • Exposure to HFA: severe pain on exposed skin immediately or more often several hours after exposure despite no physical burns observed.
  • Ingestion of HFA: small amount of highly concentrated HF can severely damage internal organs and may even be fatal.
  • Exposure to HF gas: at low concentrations will result in eye, nose and respiratory irritation. At high concentrations, it may be fatal due to the accumulation of fluid in the lungs or cardiac arrhythmia.

Long-term impacts of short contact with HF/HFA: 

  • Survivors of inhalation of HF often suffer from chronic lung disease.
  • Survivors may suffer from permanent visual problems and damage.

(Centers for Disease Control and Prevention, 2018)

Immediate intensive care treatment is required when exposed to HF/HFA. The damage of HF/HFA to the body can continue for weeks and will have lasting impacts on the person’s health (Centers for Disease Control and Prevention, 2018; Gad & Sullivan, 2014). 

HF is one of the main toxic gas released from the combustion of batteries (refer to chemical equations in the previous blog). Although many studies about the combustion of batteries and toxic gas release have been done, few have released exact amounts of HF gases produced when a battery burns (Larsson et al., 2017). Additionally, as the different battery manufacturers and battery types contain different variations of chemical compositions, it is difficult to specify the exact amount of HF gas released for a battery with a certain capacity (Larsson et al., 2017) (Figure 1). Generally, pouch cells tend to produce the highest concentrations of HF (Larsson et al., 2017). 

[A] possible explanation would be that hard prismatic and cylindrical cells can build a higher pressure before bursting, rapidly releasing a high amount of gases/vapours from the electrolyte. Due to the high velocity of the release and thus the short reaction time, combustion reactions might be incomplete and less reaction products might be produced. – Larsson et al., 2017

Figure 1: HF released during the burning of 7 different types of batteries at different SOC (Larsson et al., 2017)

From the experiments conducted by Larsson et al. (2017), they also found that the state of charge (SOC) of a battery will also affect the rate of HF released when the battery burns. Batteries at 100% SOC tend to have more extreme heat release and flames (Larsson et al., 2017). Experiments conducted on the same type of battery also found a clear correlation between the SOC of the battery and the rate of HF produced over time (Larsson et al., 2017; Zhang et al., 2022) (Figure 2). Similar experiments on different types of cells conducted showed similar results (Larsson et al., 2017). 

Figure 2: Correlation between the rate of heat release and concentration of HF over time at different SOC (Larsson et al., 2017)

 

Reference List

Centers for Disease Control and Prevention. (2018, April 4). CDC | Facts About Hydrogen Fluoride (Hydrofluoric Acid). CDC. https://emergency.cdc.gov/agent/hydrofluoricacid/basics/facts.asp 

Gad, S., & Sullivan, D. (2014). Hydrofluoric Acid. Encyclopedia of Toxicology, 964–966. https://doi.org/10.1016/b978-0-12-386454-3.00853-8 

Larsson, F., Andersson, P., Blomqvist, P., & Mellander, B. E. (2017). Toxic fluoride gas emissions from lithium-ion battery fires. Scientific Reports, 7(1). https://doi.org/10.1038/s41598-017-09784-z 

Marx, C., Trautmann, S., Halank, M., & Weise, M. (2005). Lethal intoxication with hydrofluoric acid. Critical Care, 9(Suppl 1), P407 (2005). https://doi.org/10.1186/cc3470 

Zhang, L., Duan, Q., Meng, X., Jin, K., Xu, J., Sun, J., & Wang, Q. (2022). Experimental investigation on intermittent spray cooling and toxic hazards of lithium-ion battery thermal runaway. Energy Conversion and Management, 252, 115091. https://doi.org/10.1016/j.enconman.2021.115091