Leon Prewer started working as a linesman with the HEC in 1977.

He was still with the company when it was broken up and transferred to Aurora Energy before moving to Geelong in 2002 as a contractor with Powercor, where he worked until February this year.

As an HEC linesman he was responsible for line work and maintenance, which required him to "cut scrub and treatment under the lines" in the state's North-East.

The scrub treatment included "mixing up diesel with [herbicide] 2,4,5-T, putting it in a spray pack and spraying it", Mr Prewer said.

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Sturdy boots were the only safety equipment Mr Prewer and his workmates were required to wear, along with overalls.

"There was no protective anything," he said.

They were often covered with the chemical spray as they worked, with it spraying on their clothing and skin, Mr Prewer said.

Mr Prewer is undergoing surgery next week for a slow-growing lymphoma tumour in his oesophagus.

While his doctor has not said the tumour is related to his past chemical exposure, Mr Prewer "thinks it could be related, after years and years of using this stuff".

Other former HEC employees Mr Prewer worked in had similar health issues, he said.

Mr Prewer has not spoken with TasNetworks about its investigation into former employees' chemical exposure between the 1960s and 1980s, but has spoken with Communications, Electrical and Plumbing Union of Australia (CEPU) organiser Lee Archer.

TasNetworks chief executive Lance Balcombe said the organisation would continue to provide "all concerned current or former employees with support, including health checks".

"Our primary focus is the wellbeing of all our current and former employees, 78 of whom have contacted us with concerns and questions about the historical use of the herbicide," Mr Balcombe said.

"We are speaking with all these people and have been conducting meetings around the state, which will continue over the coming weeks.

"The best action we can take to respect any concerns people may have, and to make sure we get all the facts, is to go through a thorough and rigorous process. Our focus is getting it right, not just getting it done," he said.

Current or former employees who think they may be affected can visit tasnetworks.com.au or worksafe.tas.gov.au or phone 1300 366 322.

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