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Explosion or fire of pentane released from expandable polystyrene (EPS) foam blocks

What is the potential risk?

Expandable polystyrene (EPS) foam blocks may release highly flammable pentane gas. If this gas is ignited, it could cause an explosion, which may injure workers.

EPS is a synthetic foam material that is used in a number of applications, including in the construction of roads and embankments, as a lightweight fill, and in insulated pavement. Fugitive off-gassing of pentane gas may be released from EPS foam blocks for a period of time after manufacture. If there is a source of ignition, such as electrical equipment, welding activities, or static electricity, in the presence of released pentane gas, it may be ignited, potentially causing an explosion.

There have been incidents of explosions due to the ignition of pentane gas released from EPS foam blocks in B.C. EPS foam blocks are used in other applications in B.C., which may also pose a risk of an explosion that may injure workers.

Workers who may be at risk of injury in the event of an explosion of pentane released from EPS foam blocks include workers involved in the manufacture, storage, and transport of EPS foam products, as well as workers involved in road construction, maintenance, or repair. Other workers who may be at risk include those who are installing or performing maintenance activities near EPS foam blocks.

What industries may be at risk?

  • Manufacturing
  • Construction
  • Transportation
  • Marine
  • Warehousing

How can I reduce the risk in my workplace?

As an employer, you need to know if there is the potential for the risk identified in this advisory to be present in your workplace. It’s your responsibility to regularly inspect your workplace, and to ensure that your safety procedures and practices control the risk. The following information highlights some of the sections of the Occupational Health and Safety (OHS) Regulation and Guidelines that are most relevant to this risk.

Wherever EPS products are stored, manufactured, and used, employers must ensure that adequate time has been allowed for the products to safely cure and off-gas in a well-ventilated location, and away from sources of ignition, before installation.

Part 5 of the OHS Regulation addresses flammable gases/vapours. It requires the following if it is not practicable to maintain the airborne concentration of a flammable gas or vapour below the applicable exposure limit (for example, in a temporary situation or an emergency):

  1. only the minimum number of workers necessary for the work may be exposed,
  2. every worker exposed must be adequately trained and equipped to safely perform the required duties,
  3. the concentration of the flammable gas or vapour must not exceed 20% of the lower explosive limit (LEL).

In addition to the above, Part 5 goes on to outline additional duties the employer must perform to ensure worker safety.

The BC Fire Code also places additional duties on the employer regarding the control of risks relating to the storage and handling of flammable substances.

Publication Date: Jan 2015 Asset type: Risk Advisory Reference: RA 2015-41