A former technician at Norwich City College, who claims his work there left him with lead poisoning, has started a High Court compensation bid.
Richard Jones, 60, of Bromham, Bedfordshire, said while working at the college, between 1982 and 1985, he handled three tonnes of lead a year.
He is claiming six-figure damages from Norfolk County Council which ran the college during that period.
The council has argued the case was started too late.
The court heard Mr Jones had worked in the college's plumbing and heating department.
He said he only realised the severe impact exposure to so much lead was having on his health when he gave blood more than 10 years later.
Toxic levels of the metal were found in his body.
Mr Jones's barrister, Andrew Roy, told London's High Court that when Mr Jones raised concerns about his working environment he was "positively assured" by the council that the level of his exposure to the metal was safe.
Mr Roy said any concerns he might have had were "dispelled" by that.
The truth only began to emerge in 2006 when Mr Jones made one of his regular blood donations and the toxic levels were found.
By that time, Mr Jones had already been suffering from unexplained pain in his abdomen and joints for some time.
He was put on an intensive course of medication to remove the lead from his bone marrow.
At a preliminary hearing Norfolk County Council attempted to persuade the court Mr Jones started his case too late and that his claim should be dismissed because of the delay.
However, Mr Roy insisted that Mr Jones had relied on the assurance that his workplace was safe.
Recognising the importance of the case, Judge Eccles has reserved his decision on that issue and will give his ruling at a later date.
He said he hoped to give his judgment within the next two weeks.