It’s silent, invisible and viciously unforgiving. Sniff it and by the time you can say “hydrogen sulfide” you might be dead.

Thankfully today the offshore industry has the tools to detect it in its smallest concentration and to set off an alarm protecting those nearby before it can kill.

Heavier than air it has, in its weaker version, the foul smell of rotten eggs. It processes the menacing qualities of being corrosive, flammable, explosive and when in comparatively minor amounts, extremely poisonous. H₂S, in its formula ID, is a constant threat in three major industries, the offshore, farming and fishing.

Recently in Denmark two fishermen died, their catch rotting without ice gave off the gas, they went into the hold and that was that. Hardly a year goes by without a farmer being killed by it. Last year in Northern Ireland a rising rugby star went into a silo to rescue his overcome brother who had gone in to pull out his overcome father who had gone in after their dog. They all died within seconds of exposure. These were the result of man ignoring nature.

Offshore Takes Lead

When nature acts on its own, but provoked by man, the consequences can be even more horrific – in China in December 2003, a land drilling well hit H₂S. At least 233 people and a thousand animals died and more than 9,000 people were treated.

Constant care and diligence to their customers has meant that there have been no fatalities offshore in the 30 years that the company Maersk H2S Safety Services has been part of the industry. They are a global company supplying breathing and detection apparatus to the world and their main warehouse in Esbjerg was impressively empty the day we visited. ‘We have just shipped our biggest ever order to Brazil, 15 containers,’ says Niels Koed Hansen, General Manager Sales at Maersk H2S Safety Services.

Terminally Toxic

Not so empty were the workshops where row upon row of detectors were going through a regular check-up and routine calibration – they detect from 5ppm, parts per million. A hundred 100ppm permanently wipes out your sense of smell, 1000 wipes you out – to try and gain some perspective, that’s the same as putting one teaspoon of poison into six litres of water and every drop in the bucket becoming terminally toxic.

There’s only one thing worse than being killed by H₂S gas according to instructor Claus Thorberg Hansen, and that is surviving it. He recently had a Canadian on a course who had been subjected to 250ppm – he’d been in medication for over two years and parts of him, like his lungs and sense of smell, will never be quite the same again. This was all because he walked past a very minor occurrence. He caught a whiff, others with him didn’t, but the whiff caught him. By comparison to other survivors he got of fairly lightly.

Claus had just come from training another group of rig workers, putting them through the disorientating darkened container filled with what look like oversized animal cages. They had to feel and fumble their way to safety. A large part of the survival process is in not panicking, in order to put on safety equipment correctly so it doesn’t allow any gases to sneak past.

Old Wells, New Dangers

The main role of the company is in supplying the equipment and then making sure that everyone on board knows what to do. Because of this there is a certain amount of training on the rigs as well as a constant need for a company rep to be there in regions where the gas is even a remote possibility.

In the drilling world there are areas where you are more likely to come across the gas, it’s called anywhere. Of course there are regions where it hasn’t been present but since it is created by the bacterial breakdown of organic matter, it is virtually part of the same oil and natural gas evolution process.

H₂S can even occur in instances where it wasn’t originally present. Some of the original wells in the North Sea are being revisited because better drilling techniques now make oil and gas deposits, which were once too expensive or difficult to reach, retrievable. In the short time since they were declared non-operational, bacteria has created pockets of H₂S.

Hydrogen Sulphide is a substantial safety concern in the oil industry, but far from the only gas encountered during drilling operations. This emergency call was about high concentrations of CO gas.

The most common and toxic gasses encountered in the oil industry are H₂S, CO, CO₂, SO₂, and CH₄.

Saturday morning we received an emergency call out from a Norwegian operator, as a regular well permanent plug and abandonment job went wrong, prompting a high concentration of CO in the old mud. Inhalation of CO in high concentrations is dangerous, and even deadly in concentrations at or above 12,800 ppm.

Before the arrival of our safety supervisor, the platform mud system had been seriously contaminated with a high concentration of CO and the lack of contingency plans for the presence of CO placed the forthcoming operations under high risk. The safety supervisor’s role was to advise on proper risk assessment for the handling of CO and ensure the operations could continue without jeopardizing the safety of onboard personnel.

Exposure to CO can cause nausea, dizziness, headaches and collapse. Inhalation overexposures may be fatal.

Client Feedback

Throughout your stay on the rig you have shown a very professional attitude and have helped us get a clear understanding of the problems we have faced and how to deal with them in the best possible way. On behalf of the crew, I would like to thank you for all your good work.

We keep hearing that the cost of a barrel of crude oil rises and falls and as it does the whole world shudders. Today we almost enjoy filling up the car, but then we pick up the paper to see companies trimming back because cheap oil to them means a production crisis. Through it all the news talks barrels, but what exactly is a barrel?

First of all in oil terms it is American, and not to be confused with the imperial measurements. There are 42 US gallons in a barrel, that’s an inconvenient 158.98722 litres, and the contents, when petroleum products or alcohol, are referenced at 16 degrees Celsius. In the 1860’s oil in the Pennsylvania fields was collected in whatever they had at hand, clearly something needed to be standardised. They pick up some old English wine barrels and that was that. The gasoline oil drum carries a further 13 US gallons.

But what exactly do you get from a barrel of crude? To start off to further confuse things you get an extra 6.43 gallons on top of the 42. This is due to additional elements, such as alkylates, that are added during the refining process. Crude oil varies but a typical barrel* is expect to yield a little over half (51.4%) as petrol, then there’s 15.3% diesel, 12.3% jet fuel, gas 5.4% and coke at 5%.

The barrel isn’t yet finished, residual fuel oil, the stuff that drives heaters makes up 3,3% and LPG is a further 2.8%, asphalt lubricants and other refined products make up the remaining 4.1%. A barrel of oil is a bit like a Chinese chicken, every part is used for something.

So if it produces 51.6% in petrol that’s 94.6 litres of petrol from a barrel which cost, in total, recently $50. When you consider that about 60% of what you pay at the pump in the UK and Denmark is tax, you start to see why the industry is presently looking down the butt of a barrel.

We are pleased to announce that we have achieved ISO 9001:2008 certification from DNV GL for our Quality Management System.

Maersk H2S Safety Services is committed to providing each and every client with a wide range of high quality, professional services tailored to their individual, specific needs.

We aim to achieve this commitment by operating in accordance with our management systems, focusing on constant improvement, value for money, on-time delivery and customer satisfaction.

When dealing with safety no compromise can be made.

ISO 9001 2015