Maintenance on Auckland's Harbour Bridge has left a number of workers with lead poisoning.
The staff were paint stripping as part of reinforcement of the bridge's clip-on lanes.
Auckland Regional Public Health Service says most of the bridge was painted in the 1950s when paint contained high levels of lead.
Medical Officer of Health Dr Denise Barnfather said some men showed marked increases in blood lead level within about a month of beginning work with the paint stripping gang.
She said when the workers learned to properly wear protection equipment and decontaminate themselves after the work, their blood lead levels dropped back to normal.