The federal government's Public Works department pleaded guilty Tuesday to labour code violations in connection with an explosion three years ago in Ottawa that left one worker dead and another injured.

The explosion happened Oct. 19, 2009, at the Cliff Central Heating and Cooling Plant at 1 Fleet St., the building that heated the Houses of Parliament.

Shift engineer Peter Kennedy, 51, died after suffering second-degree burns to 60 per cent of his body and another three workers suffered minor injuries.

Public Works and Government Services Canada confirmed guilty pleas were entered on three of eight charges laid against the department after an investigation in April 2010.

The three charges Public Works pleaded guilty to are:

• Failing to develop and implement a program for the prevention of hazards in the workplace.
• Failing to develop a health and safety plan.
• Failing to provide enough training for employees.

Each charge could lead to a maximum $100,000 fine. Public Works will be in court for a sentencing hearing Jan. 18.

Investigators who visited the plant in the spring of 2010 said they found a series of basic safety violations, which are detailed in a series of directives ordering Public Works to fix the problems, obtained by CBC News in 2010.

The investigators pointed out that the plant had no proper emergency procedures, that employees hadn't been shown standard operating manuals and the company servicing the boilers was not certified to do the work.

Imposing the fine would be purely symbolic, since the money from one federal department would go right back to the federal government.

The plant was decommissioned after the blast. A temporary plant constructed in the interim cost $42 million.