Workplace labels and other identifiers

Hazardous products rarely stay in their original containers. They are poured into spray bottles, decanted into smaller jugs, mixed in tanks, piped through systems and produced inside processes. Every time a product moves out of its supplier-labelled container, hazard information has to move with it. Workplace labels and other identifiers make sure that workers can identify what is in every container and how to handle it safely. This lesson explains when workplace labels are needed, what they must contain, the exemptions for portable containers used immediately, identification of piping and process vessels, products produced in the workplace, laboratory labels, alternative rating systems such as NFPA 704 and HMIS, and practical labelling programs.

When a workplace label is needed

Under federal, provincial and territorial WHMIS regulations, a workplace label is generally required when a hazardous product is decanted (transferred) from its original container into another container; when a hazardous product is produced in the workplace and used there; when a supplier label is lost, damaged or illegible and the employer chooses a workplace label instead of a replacement supplier label, where permitted; and when products are received in bulk without supplier labels. The workplace label is simpler than a supplier label because the detailed information is available on the SDS and through training.

Content of a workplace label

A WHMIS workplace label must include three elements:

• The product identifier, matching the SDS.
• Information for the safe handling of the product, which may include pictograms and other supplier label information.
• A statement that an SDS is available, if one exists.

Workplace labels may be in any format, and many employers use pre-printed labels with spaces for the product name and GHS pictograms. They must be legible and in a language workers understand. Some jurisdictions require workplace labels to be in English and French in certain situations; check your jurisdiction.

Portable containers used immediately

Most jurisdictions exempt portable containers from workplace labelling when the product is transferred into the container and used immediately, typically within the same work shift, by the person who filled it, and the container remains under that person's control. However, the container must still be identified in some way, such as by marking the product identifier, if it will not be used immediately or will be left unattended. Because the exemption is narrow, many employers label every portable container to avoid confusion.

Piping, vessels and process equipment

Hazardous products in pipes, piping systems with valves, process or reaction vessels, tank cars and similar equipment do not need workplace labels, but employers must identify them by any means, such as colour coding, stencils, signs or labels, and workers must be educated in the identification method. Tanks and vessels often carry signs giving the product name and hazards, and pipes are commonly marked with labels and arrows showing contents and flow direction, following standards such as CSA B149 for gas piping or ASME A13.1 for pipe marking.

Products produced in the workplace

When an employer produces a hazardous product in the workplace for use there, such as a mixture made on site, an intermediate in a process or a by-product, the employer must classify it, label it with a workplace label (or a supplier label, if it will be sold), and prepare an SDS if one is required. Hazardous waste produced in the workplace must be identified with signs or other means and handled safely, and workers must be educated about it. Fugitive emissions, such as welding fumes or exhaust gases, are covered by general OHS duties to inform workers.

Laboratory labels

Laboratories handle many small containers, samples and reagents, so WHMIS rules provide some flexibility. In laboratories, products from a laboratory supply house and samples for analysis may be labelled with modified information in certain circumstances, and products in a laboratory that are under the control of trained staff may be identified with the product identifier only, depending on the jurisdiction. Laboratory staff must still have access to SDSs and full hazard information.

Alternative rating systems: NFPA 704 and HMIS

Many workplaces also use rating systems that predate the GHS, especially in the United States. The NFPA 704 "fire diamond", published by the National Fire Protection Association, uses a diamond divided into four coloured sections: blue for health, red for flammability, yellow for instability and white for special hazards such as reactivity with water (W with a line through it) or oxidizers (OX). Each coloured section carries a number from 0 to 4, where 4 is the most severe. NFPA 704 is designed for emergency responders, giving a quick view of hazards on buildings, tanks and storage areas. The Hazardous Materials Identification System (HMIS), developed by the American Coatings Association, uses coloured bars with similar numbers plus a letter code for PPE.

The crucial point is that these systems number hazards in the opposite direction to the GHS: in NFPA 704 and HMIS, 4 is the most severe and 0 the least, while in the GHS Category 1 is the most severe. A product rated 4 for flammability in NFPA terms might be GHS Category 1 flammable liquid. Confusing the two can lead to dangerous misjudgements. NFPA ratings are also based on emergency conditions, such as fire, rather than routine workplace exposure.

In Canada, the NFPA 704 diamond is sometimes used for fire department information on buildings, as required by some fire codes, but it does not replace WHMIS labels. If used as part of workplace labelling, workers must be educated on its meaning, and the WHMIS requirements must still be met.

Building a labelling program

An effective labelling program includes a written procedure explaining when and how containers are labelled; a stock of pre-printed workplace labels near decanting points; a rule that no unlabelled container may be used; regular inspections of storage areas and work areas for missing or damaged labels; identification of pipes, tanks and process equipment; procedures for labelling products produced in the workplace and waste; and training so that everyone understands the labels used, including any rating systems. Colour coding of containers, such as a specific colour for each cleaning product, can help but should not replace written identification, because colours alone are easily misunderstood.

Labelling in specific situations

Some situations need extra thought. In cleaning services, many dilutions are prepared from concentrates using dispensing systems, so pre-printed labels for each diluted product, applied every time a bottle is filled, are essential. In laboratories, many small containers of reagents, solutions and samples need labels with the chemical name, concentration, hazards, date and preparer's initials. In food service, chemicals must be kept separate from food and never stored in food containers. In maintenance and construction, products are often moved between sites in smaller containers, which need labels that survive outdoor conditions. In schools, products used by students in science classes and workshops need clear labels and supervision. In each case, the principle is the same: anyone who picks up the container should be able to tell what it contains and how to handle it safely.

Waste containers

Containers of hazardous waste also need identification. Waste is often a mixture of products with uncertain composition, which can be more hazardous than the original products. Waste containers should be labelled with their contents as accurately as possible, the hazards, and the date accumulation started, following environmental and workplace rules. Never add waste to a container without knowing what is already in it, because incompatible wastes can react.

Signs and placards for storage areas

Signs at the entrances to storage rooms, flammables cabinets, gas cylinder cages and process areas warn workers and emergency responders of the hazards inside. Signs should be clear, visible and accurate: a "Flammable liquids — no smoking or open flames" sign on a storeroom door, a "Corrosives" sign near acid storage, or a "Compressed gases" sign at a cylinder cage. Outdated signs, such as signs for products no longer stored, should be removed so that warnings remain credible.

Keeping identification up to date

Identification systems drift over time as products change, containers are reused and staff turn over. Periodic walk-throughs of the workplace, checking every container, pipe and storage area against the inventory, catch problems early. Involving workers in these walk-throughs builds awareness and often reveals containers that would otherwise be missed, such as bottles stored in personal lockers or products brought from home.

Practice: decide what each container needs

Consider these situations and decide what identification each needs. A drum of hydraulic oil delivered with a supplier label: keep the supplier label legible. A mop bucket filled with diluted floor cleaner and used immediately by the cleaner who filled it: may be exempt while in use, but a label is good practice. A spray bottle of disinfectant left on a cart for the next shift: needs a workplace label. A pipe carrying caustic solution through a plant: needs pipe identification such as labels with contents and flow direction. A batch of adhesive mixed on site for use over several days: needs classification and a workplace label, with an SDS where required. A bucket of waste solvent: needs a waste label. Working through such cases helps make labelling rules practical.

Workplace labels and language

Workplace labels should be written for the people who use them. If workers speak different languages, consider bilingual or multilingual labels, or symbols supported by training, so that everyone can understand them. Keep wording short and direct, such as "Corrosive — wear goggles and gloves", and make product names large enough to read at a distance. Test new label designs with the workers who will use them and adjust them based on feedback.

Electronic and coded labels

Some workplaces use barcodes or QR codes on containers that link to electronic SDS systems, making it easy to retrieve the SDS on a phone or tablet. These are helpful additions, but they do not replace the required label elements, because labels must be readable without a device, during power outages and in emergencies.

Who is responsible for workplace labels

Employers are responsible for making sure workplace labels are applied, but in practice the person who fills or creates a container is usually the one who labels it. Make it a personal rule: if you fill it, you label it. Supervisors should check that labels are applied correctly and that a supply of blank workplace labels is always available where products are decanted.