Prison authorities in South Dakota are refusing to release information on contaminated drugs made to order for an execution tonight (30 October).

The so-called ‘DIY drugs’ – doses of the barbiturate pentobarbital produced by a compounding pharmacy for the South Dakota Department of Corrections (DOC) – were used to execute Eric Robert earlier this month, with alarming results. Robert’s eyes opened during the lethal injection process, a sign that he may not have been properly anaesthetised and the execution may have been botched.

The ingredients used to make the drugs used in Eric Robert’s execution – and set to be used this evening in that of Donald Moeller – were found to have been contaminated with fungus.

However, despite these indications that the drugs may be faulty, and therefore carrying a risk of unnecessary suffering for the prisoner, South Dakota has thus far refused to disclose any information on how they were obtained.

The drugs are known to have been made by a compounding pharmacy – a service which allows batches of drugs to be made up to order, thereby allowing customers to bypass mainstream pharmaceutical suppliers which face more comprehensive regulation. The compounding pharmacy industry has been in the spotlight lately after reports linked it to a widespread outbreak of meningitis in the US.

South Dakota DOC had previously intended to use drugs they had illegally imported from a supplier in India in the executions, but these drugs expired last month.

Maya Foa, investigator for the legal charity Reprieve said: “The use of these DIY execution drugs means that we have little idea of just what is being injected into prisoners’ veins. It is no surprise that prison authorities appear so desperate to cover up any information on where they have come from, or who made them. The South Dakota Department of Corrections must come clean: it is indefensible for the ultimate punishment to be carried out in this slipshod and unaccountable manner.”