Monday, August 21 in 1916 dawned fine and sunny but would be remembered as a day of unimaginable horror and destruction.
While the war raged in Europe, at the munitions factory in Low Moor, Bradford, workers arrived to carry out work producing the explosive picric acid which was desperately needed for shell production.
Among the workers were men, women, and children.
The Low Moor Chemical Company had been producing picric acid before it was taken over by the Ministry of Munitions which upped production and, by 1916, more than 250 workers were producing around 200 tonnes of picric acid per week.
On the day in question, the factory contained around 30,000lb of picric acid which was awaiting sampling and then shipment.
According to surviving witnesses, employee James Broughton was moving 11 uncovered drums from a drying shed when, at around 2.25pm, a fire started.
Mr Broughton said he heard a ‘sizzling noise’ while unloading a drum and then saw some acid bursting into flames, which was so violent it knocked him to the ground.
According to reports published by the Bradford Historical and Antiquarian Society, the fire spread quickly into the packing shed.
Witness Fred Stobart saw the fire from the window of the chemical laboratory, while Percy Nudds saw the packing shed in flames from his confectionary shop at the corner of Cleckheaton Road and New Works Road.
He believed that an explosion was coming and at around 2.45pm his fears were borne out.
The packing shed was blown into the air, with bricks and iron falling over a wide area. One large lump of metal landed in a field near Branch Road, Scholes, around a mile away.
A witness, Mrs A Hood, was working on the top floor of Cannon Mills in Great Horton when the explosion happened.
She later recalled: “We felt the vibration, not knowing at first what it was.
“Well, we rushed into the centre of the room, all looking questioningly at each other, none of us knowing the answer.
“Our coats which were hung along a wall started swaying.
“After a minute or two we saw an orange cloud coming up over the trees in Horton Park. ‘Oh!’, I said, ‘It looks like Chemical Works at Low Moor’ – not knowing that I had hit the nail on the head.”
Around 30 minutes later there was a double explosion as a building belonging to the Munitions Company went up and then a Corporation gasometer.
One of the explosions was heard as far away as York and the air for miles around smelled of rotten eggs.
The plant’s own fire brigade tackled the initial fires before crews from Odsal arrived at the scene, commanded by Station Officer Sugden.
John Majerus, the manager of the works directed the factory’s firemen but was then not seen for a few hours.
He then came crawling out of the wreckage on his hands and knees. He was taken home and died that night from shock and breathing in poisonous gases.
Eighteen firemen based at Nelson Street were alerted and set off in their new engine, named Hayhurst.
Hayhurst came to a halt just inside the gate when an explosion occurred at 3.16pm before they had a chance to connect the hose to the hydrants.
Six firemen were killed and Hayhurst was destroyed, with parts of the fire engine later found in Heckmondwike several miles away.
Some of the six dead firemen had to be identified by the numbers on their axes.
For Frank and Ida Clarkson, it was a wedding day they wouldn’t forget. The couple were leaving a nearby chapel when the second blast happened. The waiting horses were spooked and bolted and Ida suffered cuts to her face from flying glass.
One eyewitness recalled seeing dogs running away from the scene in all directions and later to be found as far away as Huddersfield, Wakefield and Halifax.
The official casualty figure was given as 34 killed and 60 injured. The number of dead later rose to 40 and those injured to around 100.
Explosions continued for two days and the fires were still burning after three days.
Around 2,000 homes were damaged and 50 were virtually flattened.
Hightown Council School – almost three miles from the site of the explosion – was among those who put in a claim for damaged property.
The damage was huge, and the loss of life considerable, but newspapers were restricted in what they could report because there was a war on and the disaster was considered a topic worthy of wartime censorship.
Papers were not allowed to report exactly what had happened, nor give the location.
A report in the Yorkshire Observer, two days after the tragedy, stated “the loss of life was not so serious as at first seemed probable, and this was due to the fact that the fire which preceded the first explosion gave sufficient warning to enable most of the men and all of the women workers to get out of danger.”
The main news report that day was the deaths of more than 2,500 officers and men at the Battle of the Somme.
An inquest into the tragedy, held in September 1916, looked into the suggestion that German spies or saboteurs might have been responsible.
This possibility was given serious consideration as, on the day of the explosion, some of the workers who were absent were Belgians.
Absent workers were questioned and all gave satisfactory explanations for their not being at work that day.
The inquest and an Inquiry showed that there had been contraventions of the terms of the licence at the factory and of the Explosives Act.
One of the storage huts contained more than double the quantity of picric acid allowed by the licence and it was learned that containers used for moving explosives should have been covered.
An accident report concluded that the tragedy would have been avoided ‘had the discipline in the factory been of a higher order’.
It concluded that the fire was probably started by the ignition of iron picrate which was on the top of the drums.
A monument to the dead firemen was unveiled in 1924 but the workers from the plant did not have a dedication to them until 2016, the 100th anniversary when a plaque was unveiled near to the former plant on the Spen Valley Greenway.
The Low Moor History Group paid for the plaque and researched all the dead as wartime restrictions had meant that not all of the dead had been publicly named.
The dead were listed on the plaque as 28 workers from the plant, six firemen, three workers from Sharps Dyeworks, a policeman, a Lancashire & Yorkshire fireman and a member of the public called Martha Briggs.
Martha Briggs was the only female among the casualties.
Aged 59, she lived in Kellett Building on Carr Lane, Wyke, and reportedly died from a “fit of apoplexy brought on by shock resulting from the explosion.”
The blast also killed dining room attendant George Sutcliffe who was 70.
The youngest victim was 17-year-old Maurice Hainsworth, a dyers labourer of Hardy Street, Scholes, Cleckheaton.