Twenty metres below the deck of an oil tanker, daylight disappears.
Steel walls glisten with oil. Every surface is coated in thick black sludge. The air carries hydrocarbon vapours and hydrogen sulphide — a gas so toxic that even small amounts can incapacitate a person within moments. Oxygen levels can be dangerously low, and one wrong step on the greasy floor could lead to a serious fall.
For Captain DC Sekhar, this wasn’t an occasional nightmare.
It was part of the job.
During nearly two decades in the Merchant Navy, he entered and cleaned more than 150 petroleum tanks with his crew. It was exhausting, physically demanding work that the global oil and gas industry has relied on for decades.
“It is dark, greasy and slippery,” he recalls.
“Even with all the safety protocols, I would never underestimate the risk. You have oxygen-deficient pockets, hydrocarbon gases and hydrogen sulphide, all inside a confined steel structure.”
After witnessing the risks of manual tank cleaning for nearly two decades, Sekhar built BetaTANK Robotics, a solution designed to keep workers away from toxic environments.
What troubled him most wasn’t the danger alone. It was that people still had to do it manually.
“I remember thinking in the mid-1990s,” he says. “‘It’s been over 30 years since humans landed on the moon. Why are we still sending people inside oil tanks to clean sludge? If nobody builds a robot for this, one day I will.'”
He carried that promise with him for almost three decades.
Today, it has become BetaTANK Robotics, a startup developing robots that clean petroleum and petrochemical storage tanks without requiring workers to enter them.
A dangerous job the world accepted
Petroleum storage tanks are enormous.
A single tank can hold 5,000 to 6,000 cubic metres of fuel. Over time, thick layers of sludge settle at the bottom and must be removed before maintenance, inspections, or changing fuel grades.
For decades, that process has remained largely unchanged.
Workers climb into the tank, shovel sludge into heavy-duty bags, haul them to the surface using pneumatic winches, and dispose of the waste later.
“It is a very old-fashioned, almost medieval way of working,” Sekhar says.
Besides being physically exhausting, the job exposes workers to hydrogen sulphide, hydrocarbon vapours, and oxygen-deficient environments — hazards that have caused fatal accidents around the world.
And it isn’t just an Indian challenge.
“For the world, there was simply no other option,” he says. “Manual cleaning remained the standard because practical robotic alternatives didn’t exist.”
An idea born inside an oil tank
The first version of BetaTANK wasn’t designed in a laboratory.
It took shape in Sekhar’s mind while he was standing inside one of those tanks in the mid-1990s.
Surrounded by sludge and steel, he imagined a robot that could move beneath heating coils, stay close to the tank floor, and pump sludge out directly instead of relying on conventional suction systems.
These robots are built to navigate inside petroleum tanks, removing sludge while operators control them safely from outside.
The idea remained in his notebooks for years.
The biggest hurdle wasn’t engineering — it was funding.
“I always believed I could build it,” he says. “What I needed was patient capital.”
That opportunity came in 2019 during a discussion with officials from Oil India Limited.
When the company agreed to support the idea, BetaTANK Robotics was born.
Oil India invested Rs 2.55 crore, enabling Sekhar and his 10-member team to design, build and test their first robots.
Today, the startup also holds an Indian patent for its technology.
Building a robot for one of the world’s most dangerous workplaces
Designing a robot for petroleum tanks is very different from building one for a factory floor.
Inside these tanks, even a tiny electrical spark can trigger an explosion.
That’s why conventional electric motors cannot be used.
Instead, BetaTANK’s robots operate using hydraulics. Rather than electricity, they rely on pressurised fluid to power and control movement.
“Hydraulics are inherently much safer in this environment,” Sekhar explains. “They don’t create the ignition risks associated with electrical systems.”
Unlike traditional suction-based methods, BetaTANK’s robots use a pushing system to move thick sludge more efficiently from the tank floor.
The only electrical component is an explosion-certified camera, allowing operators outside the tank to remotely guide the robot while watching live video.
Achieving this level of safety required years of testing.
Every component — from bolts to hydraulic systems — had to meet stringent international Zone 0 certification, one of the highest safety standards for environments where explosive gases may be continuously present.
“It’s not just about building a robot,” he says. “You have to prove that every possible failure is still safe.”
Why BetaTANK believes its approach is different
Only a handful of companies worldwide develop robots for cleaning petroleum tanks.
Most rely on vacuum suction.
Sekhar believes that approach has limitations.
“It’s like trying to drink ice cream through a straw,” he explains. “Nature limits suction pressure. Thick sludge simply doesn’t move efficiently.”
BetaTANK’s solution works differently.
For decades, workers manually removed layers of toxic black sludge from oil tanks, facing risks from hydrogen sulphide, hydrocarbon vapours and low oxygen levels.
Instead of pulling sludge towards the robot, it pushes the sludge into an onboard pump, which ejects it using discharge pressures of five to ten bar.
According to the company, this allows thicker sludge to be removed more efficiently.
“It becomes a pushing system rather than a sucking system,” he says. “That’s why we call it second-generation robotics.”
The redesign introduced more moving parts, making certification far more challenging, but it also created a system the company believes is better suited for industrial use.
Looking beyond oil tanks
Although BetaTANK has completed testing and international certification, it is still in the pre-revenue stage.
Its first commercial deployments are expected to begin in the Middle East while regulatory approvals continue in India.
But Sekhar sees far bigger possibilities.
The startup has already developed another compact robot capable of entering underground fuel storage tanks at petrol stations through standard 24-inch manholes, cleaning them before workers enter.
His vision goes beyond robotics: create a future where no worker has to risk their life in toxic, confined or hazardous spaces. Photograph: (AI-generated using reference)
The team is also developing robots for petrochemical plants and high-temperature foundries, environments where hazardous maintenance is still largely carried out by people.
Their mission remains simple.
“Wherever a human being is working in a dangerous environment — whether it’s hot, toxic or confined — we want to take that person out,” he says.
Rather than asking people to adapt to dangerous workplaces, BetaTANK is building machines that can take on those risks instead.
Innovation begins with curiosity
For Sekhar, innovation isn’t just about technology.
It starts with curiosity.
He believes experience provides one half of innovation, while imagination provides the other.
“A seasoned technocrat has enormous experience,” he says. “But many stop imagining. Children imagine freely, but they don’t have the experience. Innovation happens when you combine both.”
His advice to aspiring deep-tech entrepreneurs is equally grounded.
From petroleum tanks to petrochemical plants and underground fuel storage, BetaTANK aims to replace dangerous human work with safer robotic solutions.
“Just because you’ve built a great solution doesn’t mean the market is waiting for it,” he says. “Be patient. Believe in yourself. Keep building.”
Nearly 30 years after making a quiet promise to himself inside a dark oil tank, Sekhar has built the robot he once wished existed.
If his vision succeeds, thousands of workers around the world may one day no longer have to enter some of the most hazardous workplaces on Earth.
All images courtesy DC Sekhar
