Plant operator Settaleki Kolomaka, 39, was cleaning industrial equipment with the high pressure tool at BlueScope's Springhill site when the incident occurred about 11am.

Wollongong police said Mr Kolomaka was cleaning out a catchment sump in an area known as the 21 Dump, when there was a mishap with the water jet.

"The water jet has hit him in the chest causing fatal injury," Chief Inspector Chris Taylor said.

A colleague unsuccessfully tried to revive Mr Kolomaka.

Australian Workers' Union Port Kembla branch secretary Andy Gillespie said it was a "tragedy".

Mr Kolomaka was working for BlueScope subcontractor Veolia Environmental Services, formerly Allied Plant Services.

Mr Gillespie said workers were being counselled and the union would meet them this morning.

"Our members are in shock, because he was a fairly popular guy and he had been there for about 10 years," Mr Gillespie said.

"It is extremely sad and these things hit people hard ... it is something that you don't get over. We are just shattered by it, we haven't had a fatality in this industry for a long time."

The site was roped off by police and Mr Kolomaka's colleagues did not return to work yesterday.

The accident is being investigated by police, WorkCover, Veolia and the Australian Workers' Union.

Mr Gillespie said the water blaster would not be used again until the cause of the accident was established.

He said it was the first accident with the equipment he had seen.

"How that particular job is going to be done now, that is what we are waiting to find out," Mr Gillespie said.

"That's why the job has been stopped - to see if there were any safety problems with his job."

Veolia Environmental Services said a thorough investigation would be done.

"Veolia is co-operating fully with police investigators and other authorities," the company said.

"The company takes safety very seriously and a full internal investigation is also being conducted.

"This is a tragic situation and Veolia extends its sympathy to the operator's family and relatives."

BlueScope Steel extended its sympathies to Mr Kolomaka's family and workmates, but declined to comment further.

DID YOU KNOW MR KOLOMAKA? PLEASE CONTACT US ON 4221 2207 OR EMAIL cos@illawarramercury.com.au