Is moisture contaminating E20 fuel? Petrol pump owners raise fresh concerns

Petrol pump operators say ethanol's tendency to absorb moisture can trigger phase separation in E20 fuel during monsoons and in coastal regions if water enters underground storage tanks.

Fresh concerns have emerged over the storage of E20 petrol, with several petrol pump owners claiming that ethanol's natural tendency to absorb moisture could increase the risk of fuel contamination during the monsoon season and in coastal regions.

The issue centres on ethanol's hygroscopic nature, its ability to attract and absorb water from its surroundings. According to petrol pump operators, this characteristic can become problematic if water enters underground fuel storage tanks, which were originally designed for conventional petrol rather than higher ethanol blends.

The concerns come at a time when videos circulating on social media have purportedly shown what appeared to be muddy or water-contaminated fuel being dispensed at some fuel stations.

Why moisture can become a problem

Petrol pump owners told The Hindu that underground fuel tanks can accumulate small quantities of water through rainwater ingress, condensation or moisture entering during fuel deliveries. If the water content rises beyond a certain level, ethanol can bind with the water instead of remaining uniformly mixed with petrol.

Industry experts describe this process as phase separation. Once it occurs, the ethanol-water mixture settles at the bottom of the storage tank, while the petrol remains above it.

Since fuel dispensing systems draw fuel from the bottom of underground tanks, vehicles could receive a water-rich ethanol mixture instead of properly blended E20 fuel if phase separation has already taken place. The Hindu first reported these concerns after speaking to three petrol pump owners and an industry veteran.

According to pump operators, such contamination may lead to starting issues or cause vehicles to stall after being driven for some distance. They say the problem often comes to light only after customers return with complaints.

Coastal areas face an added challenge

Petrol pump dealers also claim that the risk is greater in coastal regions, where underground tanks may be exposed to sub-soil water. If seals are compromised, moisture intrusion could increase, raising the possibility of phase separation.

Some operators have also expressed concerns that underground mild-steel tanks and pipelines could become more susceptible to corrosion over time because ethanol readily absorbs water. However, dealers noted that oil marketing companies (OMCs) have already replaced seals and washers in dispensing units with neoprene rubber as part of the transition to E20.

Dealers say inspections have become more frequent

According to The Hindu, petrol pump dealers have been instructed to regularly monitor underground tanks for water contamination using dipsticks coated with water-finding paste. During the monsoon, inspection frequency is reportedly increased from three checks a day to once every two hours.

If water contamination is detected, dealers inform the concerned OMC, which deploys personnel to remove the accumulated water from the storage tank.

Some dealers, however, argue that they bear the financial loss when contaminated fuel has to be discarded, despite purchasing the fuel stock from oil companies. They have also sought clearer guidelines on the disposal of contaminated fuel-water mixtures.

Indian Oil says it has 'zero tolerance' for contamination

Indian Oil Corporation Limited (IOCL) said it follows a zero-tolerance approach towards fuel contamination.

The company said it carries out regular inspections, surprise audits and scientific quality tests across its retail network. According to IOCL, thousands of surprise inspections and quality checks were conducted over the past week alone, with dedicated teams deployed to verify compliance.

The company added that strict action is taken against dealers if contamination, adulteration or any violation of prescribed fuel quality standards is established through inspections or customer complaints.

E20 rollout remains under scrutiny

India's Ethanol Blended Petrol (EBP) Programme aims to reduce crude oil imports, improve energy security, support domestic agriculture and lower vehicular emissions by increasing the share of ethanol in petrol.

However, the nationwide rollout of E20 has sparked debate over its impact on vehicles, fuel infrastructure and storage systems. In recent weeks, the Ministry of Petroleum and Natural Gas has issued clarifications addressing concerns surrounding E20, while automobile manufacturers have also reiterated that newer E20-compliant vehicles are engineered to operate safely on the fuel.

The latest claims from petrol pump operators shift attention from vehicle compatibility to the storage and handling of E20, highlighting the importance of preventing water ingress into fuel infrastructure, particularly during the monsoon.

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