Ethanol: Associated hazards and safety measures 

Ethanol, also known as ethyl alcohol is a renewable fuel derived from plant or waste materials. Ethanol can be used for a wide range of applications, including its role in fuel cells, its utilisation as an engine fuel and an additive for enhancing fuel performance, as well as its application as a universal solvent. Furthermore, as a renewable energy source, ethanol presents an opportunity to reduce reliance on fossil fuels, thereby contributing to the reduction in greenhouse gas emissions.  

Despite its benefits as a renewable energy source and its role in mitigating carbon footprint, ethanol comes with inherent risks that have resulted in notable incidents. These events have underscored the importance of safety and risk management in handling this biofuel. 

This article explores the risks associated with ethanol and outlines potential approaches to prevent and mitigate these hazards to ensure safety and prevent undesired events.

Understanding ethanol hazards

Understanding the hazards associated with ethanol is crucial for ensuring safety in its production, storage, transportation and use.

Ethanol is flammable 

Due to its highly flammable nature, ethanol carries a substantial risk of causing fires and explosions, which underscores the importance of being aware of its flash point. Ethanol’s flash point at atmospheric pressure is around 14 °C (57.2 °F), indicating that its vapours can catch fire at or above this temperature when exposed to an ignition source. When it burns, it has a smokeless blue flame that is not always visible in normal light.

When the vapour mixes with air reaching a concentration between flammability limits, it becomes flammable and, since it’s heavier than air, it stays along the ground as it spreads. The vapour may travel considerable distances and potentially cause fires and explosions far from the source and flashback. Consequently, spaces that are not well-ventilated, particularly those below ground levels such as trenches, conduits, shafts, and sewers, are at a higher risk for the build-up of flammable substances or mixtures, where a Vapour Cloud Explosion (VCE) may occur. 

If a vessel containing liquid ethanol suffers from thermal exposure due to a nearby fire, there is a possibility of a BLEVE (boiling liquid expanding vapour explosion) due to its relatively low boiling point (see Table 1). 

Table 1 provides more information on the chemical and physical properties of pure ethanol. 

Properties	Details
Physical description	Clear, colourless, mobile liquid with a characteristic odour and a burning taste
Flash point	14.0 °C / 57.2 °F (closed cup)
Boiling point	78.24 °C / 172.83 °F
Vapour density	1.59 kg/m3 (heavier than air – will spread close to the ground)
Liquid density	789.3 kg/m3 at 20 °C / 1.53 slug/ft3 at 68 °F (less dense than water – will float)
Flammability range	Lower Flammable Limit: 3.3% Upper Flammable Limit: 19%
Auto ignition temperature	363 °C / 685 °F
Solubility	Miscible with many organic solvents

Table 1. Ethanol chemical and physical properties¹. 

Ethanol poses health risks 

Ethanol is harmful by ingestion, inhalation, or by skin absorption. Inhaling ethanol vapour can lead to irritation of the nose and throat, resulting in coughing or irritation of the respiratory system. Ingestion can lead to a series of symptoms including headaches, nausea, vomiting, and a state of intoxication. Additionally, exposure to the skin and eyes may cause irritation. 

Contamination from ethanol could harm the environment 

Apart from its flammability and health hazards, ethanol also presents environmental concerns, particularly in the event of a spill. If ethanol enters water systems, it can reduce oxygen levels, which harms aquatic life. Moreover, depending on the raw materials chosen in the production process, ethanol has environmental impacts, including land use changes and water resource depletion. 

Ethanol incident examples 

The hazards of ethanol are not just theoretical, as several incidents have underscored their real-world implications.

For instance, a fire broke out during ethanol tank maintenance in India in December 2023, resulting in one fatality and one injury².

In July 2023, an explosion occurred at an ethanol plant in South Dakota, which was caused by ethanol vapours³ during a restart process⁴.

Furthermore, in April 2023, an explosion at a Nebraska ethanol plant tragically took the life of an employee and injured another employee along with three contractors during routine maintenance and repairs of a whole stillage tank ⁵.

Additionally, in March 2023, a significant incident occurred in Minnesota when a train transporting ethanol derailed, causing several cars to catch fire, and leading to the evacuation of approximately 800 residents living near the crash site⁶.

These instances highlight the critical importance of prioritising safety and serve as a reminder of the consequences of neglecting appropriate safety measures. 

Proactive safety measures 

Build awareness of ethanol safety 

Raising awareness about the safety aspects of ethanol is crucial for minimising the risks associated with its handling and processing. It’s essential for ethanol plant operators to provide extensive training for their employees, ensuring they fully understand the risks associated with ethanol, including its highly flammable properties and the correct procedures for its safe handling.

Without a well-informed workforce, the likelihood of accidents increases, potentially leading to devastating fires, explosions, or environmental contamination. 

Use of Personal Protective Equipment (PPE) 

Workers in facilities handling ethanol need to be equipped with the necessary PPE to ensure their safety. This includes wearing respirators to guard against breathing in harmful vapours; overalls, gloves, boots, and face masks to protect the skin from contact with ethanol; and safety goggles to prevent eye exposure to splashes or vapours.

Such protective measures are essential not only for mitigating immediate risks but also for preventing long-term health complications associated with ethanol exposure. 

Proper handling and storage⁷ 

The handling and storage of ethanol pose significant challenges primarily due to the flammable nature of its vapours. Ethanol needs to be kept in containers that are securely sealed to prevent leakage and evaporation, accurately labelled, and have features to prevent explosions. These containers should also be stored in a cool area.

It’s crucial for facilities processing ethanol to maintain proper ventilation to avoid the build-up of flammable vapours. Removing any possible sources of ignition and employing explosion-proof tools and equipment are also critical in environments where ethanol is handled.

Additionally, when transporting ethanol in metal containers, grounding and bonding procedures should be implemented to prevent static charges. Moreover, it’s important to avoid ethanol to be in contact with incompatible materials. 

Develop emergency preparedness⁷ 

Facilities should have an emergency response plan tailored to the risks of ethanol, which includes procedures for responding to accidental releases and actions to take in case of fires. For instance, in the event of an ethanol fire, alcohol-resistant foam or water spray should be used, as a water jet may be ineffective.

Regarding spills, it’s crucial to prevent ethanol from entering confined spaces, such as sewers or waterways. The liquid should be absorbed with non-combustible materials and placed into sealed containers for disposal according to local regulations.

Monitoring and warning systems, such as detectors and alarms should be in place. Moreover, regular drills should be conducted to ensure readiness and effectiveness of the emergency response measures. 

Comply with regulatory requirements 

Facilities handling ethanol are required to comply with safety standards, codes, and regulations to prevent accidents and protect employees, the public, and the surrounding environment. These requirements differ across countries and regions but generally cover guidelines on the proper storage, handling, and transportation of ethanol, as well as air quality and waste management.

To comply, facilities are obligated to put in place safety measures against fires, explosions, and unintended releases, and to equip themselves with emergency response plans. Staying informed about requirement updates and industry best practices is essential for ensuring ongoing compliance and showcasing a dedication to safety and environmental sustainability in the management of ethanol. 

Perform regular risk assessments 

To support regulatory compliance, ethanol handling facilities should conduct regular risk assessments and audits to ensure they align with current regulations. These regular assessments are also relevant before operational changes or during periodic reviews. 

Studies such as Process Hazard Analysis (PHA), HAZID (Hazard Identification), HAZOP (Hazard and Operability Study), What-If, and consequence analysis are instrumental in identifying the hazards present within the facility and evaluating and estimating the potential consequences of these hazards. These methodologies allow for a systematic examination of processes to identify where and how operations might pose risks. 

Following the identification and consequence estimation of hazards, it’s crucial to evaluate the risks either qualitatively or quantitatively. This evaluation helps determine the severity and likelihood of each risk by assigning a value and ranking that can be compared against predefined risk criteria. Such an approach enables facilities to classify risks as either acceptable or unacceptable, based on their potential impacts, frequencies, and probabilities. Results from the evaluation should then inform the implementation of appropriate protection, prevention, and mitigation measures. 

While risk assessments can be performed internally, leveraging third-party experts offers a valuable opportunity to bridge gaps in in-house experience and knowledge. External specialists bring a fresh perspective and specialised expertise, enhancing the comprehensiveness and accuracy of the risk assessment process. For facilities opting to undertake risk assessments in-house, there are advanced tools available to facilitate effective risk assessments, such as RISKCURVES from Gexcon, an advanced software tool to perform Quantitative Risk Analysis (QRA) to assess the total risk of storing, handling, and transporting dangerous substances in process industries. 

Conclusion 

While ethanol serves as a renewable alternative to fossil fuels, its associated hazards cannot be overlooked. By understanding the risks associated with ethanol and prioritising safety, the benefits of ethanol can be harnessed effectively and safely. It is the responsibility of businesses, industries, regulatory bodies, and individuals to work together to ensure that the handling and use of renewable fuels like ethanol does not compromise safety and health. 

References

1. PubChem (no date) Ethanol. Available at: Link 

2. The Hindu (2023) One dead, one injured in a blast at Indian Oil Corporation’s terminal in Chennai. Available at: Link 

3. Agweek (2023) Ringneck Energy back in action following explosion. Available at: Link 

4. SDPB Radio (2023) Investigation rules Onida ethanol plant explosion accidental. Available at: Link  

5. KSNB (2023) One dead, four injured in explosion at Wood River ethanol plant. Available at: Link

6. NBC News (2023) Train carrying ethanol derails and catches fire in Minnesota, forcing residents to evacuate. Available at: Link

7. International Labour Organization (no date) Ethanol (Anhydrous). Available at: Link

Writers

---