What Are Designated Substances?

Construction workers are exposed to various health issues which could be related to many chemical, biological, or physical substances used. Eleven of these chemical agents are termed as Designated Substances, which are also identified as ‘risky’ by the Ministry of Labor under the Occupational Health and Safety Act.

They are:

  • Acrylonitrile – found in industrial chemical processes
  • Arsenic – natural element found in the earth’s crust
  • Asbestos – old ceiling tiles and pipe insulation
  • Benzene – liquid found in petroleum products
  • Coke Oven Emissions
  • Ethylene Oxide – found in industrial chemical processes
  • Isocyanates – used to produce pesticides
  • Lead – found in old paint and plumbing solder
  • Mercury – found in thermometers and laboratories
  • Silica – fine sand dust from concretes
  • Vinyl Chloride – forerunners to polymers


The Occupational Health and Safety Act came into existence in the year 1970. It is a US labor law for private sector and federal government with respect to occupational health and safety of the workers. However, there is a different act which regulates the designated substances – Designated Substances Regulation (Reg. 490).

Identifying Designated Substances

It is very important to identify designated substances at work place and take significant precautionary measures. If we talk about a construction site, one of the vital roles of the project owner is to identify the designated substances (if any) and make a list of them. This is a legal process and should be followed before the work starts.

When there is a disparity in the quantity of material entering and evacuating the workplace, it is easy to identify the amount of exposure of the designated substances to the workers. This imbalance is basically due to immoderate air or water discharges that the workers come in contact with.

Popcorn ceiling

Organizations, other than construction sites, have to analyze the work procedures, and evaluate the possibility of designated substances being exposed to the workers. This analysis is to decide if there could be a health issue for workers, and whether a control program is required. If any of the designated substances are present in a work place, a control program is introduced which includes engineering controls, work and hygiene practices, record checks, and medical inspection, if required.

The evaluation will incorporate the following:

  • knowledge of the designated substance with respect to its utilization, storage, handling, and disposal
  • factual and possible exposure of laborers to the substance
  • strategies and techniques required to control that exposure


Keeping one with self, a copy of this inspection report is shared with each: the local Joint Health and Safety Committee, and Environmental Health and Safety unit for consultation.

The main purpose, in both the cases, is nothing but complete safety of the workers. The substance which can cause harm is identified and specialists deal with the situation in the most secure manner.

Popcorn ceiling

Risk Factors Related with Exposure to Designated Substances

No immediate signs of trouble are seen in any worker exposed to designated substances. The process is slow but sure to harm them. However, every individual has different immune system. Some are affected faster when exposed to these substances. Allergic reactions are the most common and somewhat faster factors noticed. Others include: cancer related issues, liver and lung diseases, and damaged nervous system.

Liquids containing remarkable amount of aromatic hydrocarbon content could be risky if exposed to humans. Similarly, solvents with high benzene concentration can enter through the skin and cause serious concerns.

While working on a construction site or an organization, take every single precaution when it comes to personal health. Site owners/employers should also be alert and carry out all the necessary measures related to their workers’ onsite safety.


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