About five pounds (two kilograms) of sweets were sold to the public, leading to around 20 deaths and over 200 people suffering the effects of arsenic poisoning.

Three men were arrested—the chemist who sold the arsenic, his assistant and the sweet maker—but all three were acquitted after the judge decided it was all accidental, there was no case for any of them to answer.

[4][b] The adulteration fell into three categories: firstly were harmless additions, such as chicory in coffee, adding flour to mustard and watering down milk.

[6] The chemist Arthur Hill Hassall was prominent in the field of food analysis as an analytical microscopist who established levels of adulteration.

[1] In the Victorian era, arsenic was an ingredient in several household products, including medicines (for external and internal use), candles, wallpaper, soft furnishings and colourants for foods.

Any arsenic not to be used for medicinal purposes was to be coloured with soot or indigo to differentiate it from other white powders on sale.

[1] Although the Act controlled the method of sale, it did not bring an end to arsenic-related problems or the widespread use of arsenic in household goods.

[18] William Hardaker, known to locals as "Humbug Billy", sold sweets from a stall in the Greenmarket in central Bradford.

Hardaker purchased his confectionery from Joseph Neal, who made the sweets in Stone Street a few hundred yards to the north.

[21] In the week before the regular Saturday market, Neal was due to make a batch of lozenges for Hardaker but had run out of "daft".

Neal asked his lodger, James Archer, to visit a druggist in the town of Shipley five miles (eight kilometres) away to purchase the gypsum.

[1][22] The druggist, Charles Hodgson, was ill in bed; his assistant, William Goddard, was on duty and had been told the daft was in a barrel in the attic.

[33] The chief constable, William Leveratt, had been kept abreast of developments, and deployed men to local inns and alehouses to spread warnings about the lozenges.

[35][36] By midday on the Monday—1 November—the number of dead had risen to twelve, with seventy-eight people seriously ill.[27] Police visited Neal for a second time and searched his premises more thoroughly, finding hundreds of fragments still on the drying boards used when preparing the lozenges.

[41] The magistrates met again on the Friday and determined that the three men in custody should be sent to the next York assizes for trial on a charge of manslaughter by negligence.

After hearing some of the evidence, the judge stopped the proceedings and said there was no case for Hodgson to answer; he instructed the jury to record a verdict of not guilty, which they did.

[46][47] According to the legal scholar Jillian London, "Although the Bradford incident was far from solely responsible for the passage of the 1860 Act, it was instrumental in heightening public awareness of and outrage towards adulteration".