Voice of an Angel was played as the memorial service began just before 3pm.
Locals were silent as they gathered at the street leading to the site of the blast.
Four men, three women and three young people, ranging in age from five to 59, died in the blast that took place in the Co Donegal village of Creeslough on the afternoon of Friday October 7 last year.
Robert Garwe and his five-year-old daughter Shauna Flanagan-Garwe, Catherine O’Donnell and her 13-year-old son James Monaghan, fashion student Jessica Gallagher, Celtic fan Martin McGill, Sydney native James O’Flaherty, shop worker Martina Martin, carpenter Hugh ‘Hughie’ Kelly and 14-year-old Leona Harper were killed in the explosion.
A vigil mass is to take place at 7.30pm at St Michael’s Church to remember those who died and those who were injured, and to thank the first responders to the scene.
The rescue and recovery effort, involving members of the community and emergency services on both sides of the border, was praised and sympathies were shared from across the world in the aftermath of the explosion.
A year on, no update has been given publicly on what caused the explosion.
Irish police previously said the incident was being treated as a tragic accident, with a gas leak considered as one possibility.
An Garda Siochana said ahead of the anniversary that its investigation was continuing “as expeditiously as possible”.
It said that over 1,350 lines of inquiry had been actioned and more than 900 statements had been taken.
Various Garda agencies are involved in the investigation and are being assisted by the Norwegian company Det Norske Veritas, which specialises in investigating and testing energy systems.
Ahead of the anniversary date, the families of those who died requested that the media respect their privacy.
Ireland’s premier Leo Varadkar said: “Our thoughts and prayers are with those who lost loved ones and the community in Creeslough today and every day. Seasimid libh.”
Ireland’s deputy premier Micheal Martin said he was “thinking of the people of Creeslough today, one year on since the terrible tragedy”.
“We remember the 10 lives lost, those injured, their families, and an entire community united in grief,” Mr Martin said on X, formerly known as Twitter.