A view of a standard cell block at Ontario's Kingston Penitentiary as seen last October. The facility is now closed. (Fred Thornhill/Reuters)

Today is the 40th anniversary of Prisoners’ Justice Day in Canada. It’s a day when thousands of inmates across the country fast and refuse to work to recognize the hundreds of inmates who have died in custody in the past four decades. Many will also wear black armbands or patches.

The John Howard Society, the Canadian Association of Elizabeth Fry Societies and other prisoners’ advocacy groups are also holding events in cities across Canada.

The annual memorial began following the death of Edward Nolan, who committed suicide in a segregation cell at Millhaven penitentiary in Ontario on Aug.10, 1974. Since then, the link between solitary confinement and mental health has been highlighted in many reports, including the high-profile death of teenager Ashley Smith.

Smith choked to death in 2007 after tying a piece of cloth around her neck while guards stood outside her segregation cell and watched. They had been ordered not to intervene unless she stopped breathing. Canada’s prison officials have promised to respond by the end of the year to more than 100 recommendations made last year following a lengthy inquest into her death.

Canada’s Correctional Investigator, Howard Sapers, has called for a ban on placing inmates who are seriously mentally ill in solitary confinement, based on research that shows it only makes them worse, not better.

And in 2012, the United Nations Committee Against Torture found Canada in violation of  the Convention Against Torture by its use of solitary confinement for mentally ill prisoners.