New export controls will further limit the ability of states already facing severe shortages of sedatives used to kill prisoners

The European Commission has imposed tough new restrictions on the export of anaesthetics used to execute people in the US, in a move that will exacerbate the already extreme shortage of the drugs in many of the 34 states that still practice the death penalty.

The EC has added eight barbiturates to its list of restricted products that are tightly controlled on the grounds that they may be used for "capital punishment, torture or other cruel, inhuman or degrading treatment or punishment". The eight include pentobarbital and sodium thiopental – the two drugs on which almost all American executions currently depend.

The EC said its move, which follows restrictions introduced unilaterally by the UK in November 2010, was designed to forward the European Union's stated mission to abolish the death penalty around the world. "The decision today contributes to the wider EU efforts to abolish the death penalty worldwide," said the commission's vice president, Catherine Ashton.

The new regulations were welcomed by the UK's business secretary Vince Cable, who pioneered Britain's export controls. "We have led the way by introducing national controls on the export to the United States of certain drugs, which could be used for the purpose of lethal injection. However we have always stated our clear preference for action at EU level and I am pleased that, following our initiative, these steps are now being taken."

Cable added that the new measure would ensure that the UK controls and others like it imposed by individual member states could not be circumvented by the movement of drugs around the EU.

Maya Foa, a lethal injection expert with the human rights group Reprieve who has led the campaign for greater controls on drugs used in US executions, said that the new regulations would be of huge importance both symbolically and practically. "This is going to force the states that still practice the death penalty to reconsider their protocols, and anything that gets them to think carefully about what they are doing has to be a good thing."

Lethal injection has become in recent years the overwhelming method of judicial killings, with very rare exceptions such as Utah, which carried out an execution by firing squad in June 2010. Some states use a triple injection comprising a barbiturate to put the prisoner to sleep followed by other drugs to paralyze the body and then stop the heart.

Other states use a massive dose of barbiturate alone – but in either case sodium thiopental or pentobarbiatal are essential to the process.

In 2009 the only American manufacturer of sodium thiopental, the Illinois-based Hospira, suspended production because it was suffering commercially as a result of having its drug connected to executions. Then this summer, a Danish manufacturer of pentobarbital, Lundbeck, blocked the sale of its product trademarked Nembutal to any penal institution in the US.

Many states still have stocks of the two sedatives, but many are running low or passing their expiry date, leading to ever more desperate measures.

In March Georgia had its last supplies of sodium thiopental siezed by federal agents acting on information that the state had imported the substance from the UK before the British restrictions had been imposed, but without a proper licence.

That did not stop Georgia, however, from executing Troy Davis in September having switched to pentobarbital.

Earlier this year the Obama administration made a direct appeal to Germany asking for supplies of the anaesthetics, only to be roundly rebuffed by the German vice chancellor Philipp Rosler. "I noted the request and declined," Rosler told Der Spiegel.

Reprieve hopes the European move will be just the start of an ever-tightening grip on medical drugs reaching US penitentiaries. Though the new restricted list covers the only two drugs currently used in American death penalties, the fear is that intrepid states will find a way round the controls by using other sedatives not on the list.

"We need to see a broad, catch-all provision to prevent any drugs from being used in capital punishment in order to ensure Europe is never again complicit in the death penalty," Reprieve's director, Clare Algar, said.

The EC, mindful of the possibility that states may try to circumvent the new regulations, says that it has the power to add other drugs to the list at will. It is also going to carry out a full review next year to see whether the controls on drugs used by US death row prisons are fool-proof.