Substances can occur in three different phases: Solid, liquid or gaseous, in chemistry usually indicated with the letters S, L and G, respectively.
In the gaseous phase, all particles (molecules) move through the air independently of each other.
A particle is a collection of molecules in the solid or liquid phase. In the case of sold particles, the lungs and alveoli can be affected. It is much easier for gases and vapours to enter our lungs through the air we breathe in. Gases can also be absorbed in our blood and affect our body internally, since blood flows to our most vulnerable organs, like the liver, kidneys and brain.
In some cases, we notice poisoning through dizziness, breathlessness, unconsciousness or worse. In that case, work has to be stopped at once, to prevent more people from falling victim as long as the source is unknown. However, we don’t always notice it immediately if we are poisoned, and hazardous substances can be a hidden killer.
The risk can occur through a single vapour, but also through the combination of two harmless gases. Because identifying gases is a fairly complex matter, chemical substances have a so-called CAS (Chemical Abstracts Service) number, which has been used to order substances for over a hundred years. Using the CAS number, you can determine which substances are involved and what the dangers are.
The human body has a number of natural defence mechanisms, like our nose hairs to capture particles, mucus and hair cells in the airways and macrophages to neutralize particles. Finally, coughing and sneezing helps to clean the airways and keep them open.
However, there are limits to our physical defences: the defence mechanism is overwhelmed by large quantities, or bypassed by very small particles. In addition, particles can infect our organs or cause allergic reactions.
Our body can no longer protect us is we are exposed to large quantities of a certain substance or to substances that are very dangerous, which is why hazardous substance in the workplace have to be identified and avoided as much as possible1.
Inhaling: Hazardous substances predominantly affect the airways, because, through breathing, we ‘suck’ the substance or vapour towards ourselves.
Absorption: Other organs, like the skin and eyes, can also be affected, because substance can be absorbed into our blood through our skin or eyes. Eye protection and standardized clothing may be necessary to protect the employee sufficiently
Swallowing: you may think you won’t ingest hazardous substances, but it happens regularly, not only during incidents, but also accidentally, through eating, smoking or drinking with unclean hands.
Injection: this is a less well-known form of exposure and perhaps the most forgotten option. Wounds caused by contaminated objects bring the substance directly in our bloodstream. That can also happen through a literal injection with contaminated needles or fluids that injected into the body under high pressure (incident).
When your organs receive insufficient oxygen, you will suffocate. When there is less than 20% oxygen in the air, consciousness is reduced. With a concentration of less than 14%, that is noticeable through deeper breathing / breathlessness, increased pulse and poor coordination. Dizziness, blue lips and poor judgement occur with less than 12% oxygen, and at less than 10%, you lose consciousness and (without aid) you will die in a matter of minutes. Oxygen can be absent, repressed or used up. In certain environments, other substances can push out the oxygen, and you can only work with an independent supply of oxygen.
When the concentration of hazardous substances exceeds the limit, it will lead to poisoning, which means that people ingest a large quantity of the substance. Through its effect, the substances causes damage to our body, which does not have to become manifest at once. The damage can also come to light years later, for instance in the case of black lungs, different forms of cancer, or liver or kidney failure.
That inventory is possible using the tool that provided by the I-SZW2. To gain insight into the exposure of your employees, you can use the various calculation programmes (approved by the I-SZW), with which you can assess the exposure on the basis of substance characteristics and exposure duration, which includes the circumstances under which the exposure takes place.
Those limits can be found in the CAS register or on the website of the ECHA (European Chemical Hazards Agency). When the limits are exceeded, the safety and health of the people being exposed are in danger.
If you are working with (hazardous) substances, you will be familiar with the MSDS (Material Safety Data Sheets) / SIS (Safety Information Sheets), which contain all the ingredients of the product, complete with their CAS numbers. The information regarding the hazardous component can be looked up using the CAS number. The manufacturer / supplier has to provide a safety sheet, both for pure substances and mixtures. These sheets need to be available during inspections.
The risks of exposure to hazardous substances have to be included in the Risk Inventory & Evaluation (RI&E).
The MSDS indicates which safety measures need to be taken when working with the substance in question. However, this can vary per task or workplace, which is why you always have to balance the recommendations of the MSDS, the work circumstances and the work comfort.
The limit is the maximum allowed concentration or quantity of a substance that an employee is ‘allowed’ to ingest during work, during a fixed reference period, often either a short period of 15 minutes, or a long work period of 8 hours.
The limit value per substance can be found in the CAS register. When, after evaluation or measurement, the exposure turns out to be too high, that risk has to be mitigated according to the Work Hygiene Strategy (WHS). Risk mitigation always uses the ALARP principle.
Employers and employees are themselves responsible for the safe handling of substance in the workplace. For most substance, a legal limit has been determined. If there is no legal limit, the company has to deduce a company limit. Employers have to set the limit to a level where there is no risk to the health of their employees. Use the ALARP principle. The website of the SER are useful tools in this respect.
The ALARP principle means: as low as reasonably practicable, the aim being to create as safe as possible a work environment. There is a grey area between meeting and not meeting the requirement. To avoid negligence, a company has to be able to demonstrate that the efforts (time, money and other resources) are proportionate to the risk reduction. If the efforts are excessive in relation to the risk reduction, the ALARP level has been reached. The principle cannot be applied to the so-called CMR substances (carcinogenic, mutagenic and reprotoxies), which have to be replaced by alternatives, no matter how expensive those alternatives are.
An employer first has to remove the source of the problem, which can be done in two ways:
- Elimination: no longer carrying out the process, no longer applying the product.
- Substitution: replacing a hazardous substance by a safer alternative.
If source measures are not possible, the employer has to take collective measures to reduce the risks. Example: placing physical protection between product and people, product in closed system.
If collective measures ate also not possible or don’t (yet) provide enough of a solution, the employer has to take individual measures.
Example: protecting the employees in cabins or work rotation.
Personal protective Equipment
If the measures listed above have no or insufficient effect, the employer has to provide free protective gear with which an acceptable level of exposure can be achieved. Example: dust masks or eye protection.
Be aware that safety is broader than personal protective gear (PPG). Ideally, every danger should be eliminated, but unfortunately, that is not always possible. That is why we provide some additional tips to broaden the concept of safety.
First of all, make your employees aware of the risks. List the products in question, as well as their hazardous ingredients and their effects. After all, many effects are invisible, as we can see in the case of asbestos and silica dust. Employees who know why they are wearing protection will be more disciplined about wearing their PPG, but also keep their hands clean, for example.
Nobody knows the work situation better than your employees, so make sure to involve them when it comes to improving work safety. In the case of larger projects, a work group can represent the entire production. They can provide input, for instance when it comes to signalling risks, testing alternative approaches or PPG. All tips can help create a significant safety improvement!
In addition, that kind of involvement also generates internal support. When people are asked to take part and give input, they can be ambassadors for the decision that have been made.