Royal Dutch Shell (NYSE: RDS.A) and Gas Networks Ireland (GNI) are working to remove odorless gas that entered the network from the country’s Corrib gas field and has curbed output since last week, Shell said on Sept. 28.

Due to a technical problem at the Shell-operated Bellanaboy Bridge gas terminal in Ireland, odorless gas entered the network, forcing GNI to ask local customers to switch off their gas meters on Sept. 22 to Sept.23, a Shell spokesperson said.

Odorless gas cannot be easily detected as it cannot be smelled. Normally odorants are added before the gas reaches customers so people can detect gas leaks by scent. Undetected gas can lead to an explosion or fire.

Gas output from the Corrib field has been reduced by 9.9 million cubic meters daily as Shell and GNI are removing the odorless gas from the network. The reduction is being extended daily, industry data shows.

“Work is ongoing to remove a quantity of odorless gas, which entered the GNI network ... flaring has occurred at the Bellanaboy Bridge Gas Terminal to remove the gas in a safe and controlled manner,” the spokesperson said.

Shell and GNI have been working to route the odorless gas back to Corrib, where disposal is taking place. The cause of the incident is unclear, but an internal investigation is under way, the spokesperson said.

At peak production, Corrib gas can meet up to 60% of Ireland’s gas needs, providing the country with a secure energy supply for up to 20 years, according to Shell data.

The Corrib gas field, operated by Shell, lies some 83 km (52 miles) off the northwest coast of Ireland, about 3 km (about 2 miles) under the seabed and in waters 350 meters (1148 ft) deep.

In July, Shell said it would sell its 45% stake in the Corrib gas venture to a unit of Canada Pension Plan Investment Board for up to $1.23 billion, marking the oil company’s exit from the upstream business in Ireland.