Dr Clive Wilfred Bird, 64, reader in chemistry in King's College, London, failed to observe the rules that it was "better to be safe than sorry" when students were doing experiments, Nicholas Wood for the prosecution said.
Mr Wood was speaking at the opening of a landmark trial at Knightsbridge Crown Court at which Dr Bird of Upminster, east London, is being prosecuted by the Health and Safety Executive for an alleged breach of the Health and Safety at Work Act 1974.
Lakhbir Pooni, 23, of Slough, Berkshire, lost the top of his thumb and part of his finger when chemicals he was preparing exploded in February 1994, demolishing his work bench and leaving him with severe injuries, Mr Wood said.
Dr Bird was the departmental safety officer at the time and had a responsibility to ensure students' safety, he added.
Dr Bird is believed to be one of the first senior lecturers to be prosecuted under the Act, which requires employers to make "a suitable and sufficient assessment" of the risks to the health and safety of persons not in their employment while engaged in work upon their premises.
Dr Bird denies failing to make a suitable assessment of the risk to the health and safety of a student at the college between October 1993 and February 1994.
Mr Pooni, now unemployed, told the court he followed "a recipe" set out by Dr Bird for experimenting with explosive chemical compounds. But he said he had not been warned that it could explode in his hands.
The hearing continues today.