Issued: April 4, 2016


At a construction project, overhead ice can accumulate on different surfaces such as the roof of a residential or commercial building, or an excavation wall, or even formwork. Large icicles can form on eaves, window frames or gutters. The accumulation of ice overhead represents a significant hazard to workers if not removed in a timely way.

Ice can accumulate after a weather event, such as an ice storm, or when the temperature conditions are suitable for the freezing of water that has accumulated on the surface of a structure or object. Ice also develops when the heat from one surface partly melts the ice or snow; the water then attaches to that surface and freezes again, which creates a layer of ice in a relatively short period of time. Icicle formation is more common (and dangerous) in milder winter weather conditions, when the sun warms the area enough to melt the ice during the day but gives way to freezing temperatures at night.

While ice falling long distances can be fatal, ice doesn’t have to fall from tall structures in order to cause damage. Icicles detaching from two-storey homes or lower levels of a multi-storey apartment or office buildings can often be enough to cause lacerations, head injuries, broken bones, and even death in rare cases. In addition, dripping water from melting icicles may pool on the ground below and refreeze, creating a serious slip-and-fall hazard.


This alert is intended to increase awareness about the safety requirements under the Construction Projects Regulation, O. Reg. 213/91. It is intended to help constructors, employers, supervisors and workers be aware of the potential hazards associated with falling ice at a construction project and ensure that the necessary precautions are taken to prevent workers from being exposed to the associated dangers.

Protective measures

Obligations under the Occupational Health and Safety Act and the Construction Projects Regulation

It is the responsibility of the constructor, the employer and the supervisor to ensure that all of the sections of the Regulation for Construction Projects are complied with on a project under construction during wintertime conditions. Special attention must be paid to the accumulation of ice both as a slip hazard for workers and when it is present as an overhead hazard.

  • Section 232 (1) of O. Reg. 213/91 states “the walls of an excavation shall be stripped of loose rock or other material that may slide, roll or fall upon a worker.”

The above section would include accumulations of ice that might form on trench walls or on the shoring system during the wintertime.

The following O. Reg. 213/91 sections may also apply in varying degrees:

  • Section 14 (3) requires a supervisor to “inspect all […] buildings and other structures, temporary supports and means of access and egress at the project to ensure that they do not endanger any worker.”
  • Section 34 (1) states “if material may fall on a worker, overhead protection shall be provided, (a) at every means of access to and egress from a building or other structure under construction; and (b) above every area where work is being carried out.”
  • Section 72 states “a work area, a route to and from a work area and a scaffold platform on which work is being performed shall be maintained at all times in a condition that does not endanger workers and, without limiting the generality of the foregoing, (a) shall be kept clear of obstructions; (b) shall be kept clear of snow, ice or other slippery material; […]”

Infrastructure Health and Safety Association

This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. Health and safety inspectors apply and enforce these laws based on the facts they find in the workplace.