Hazardous substances can cause serious ill health, such as lung disease, asthma, dermatitis and cancer, sometimes many years after exposure.

Falls from height are the most common cause of fatal injuries at work, and a major cause of serious injuries. In this module you will learn how both of these hazards are controlled.

Hazardous substances can be solids, liquids, dusts, fumes, vapours, gases or micro-organisms. Examples include:

• Chemicals, such as cleaning products, solvents, paints, adhesives and pesticides.
• Dusts, such as wood dust, flour dust and silica dust from cutting stone or concrete.
• Fumes, such as welding fumes and diesel exhaust.
• Biological agents, such as bacteria and viruses.

Hazardous substances can enter the body by:

• Breathing them in, as dust, fumes, vapour or gas. This is the most common route.
• Contact with the skin or eyes, through splashes or contamination.
• Swallowing, for example from contaminated hands when eating, drinking or smoking.
• Injection, through cuts or needle-stick injuries.

Effects include skin problems such as dermatitis, breathing problems, asthma, lung disease and cancer.

Under the Control of Substances Hazardous to Health Regulations 2002, known as COSHH, employers must assess the risks and prevent or control exposure, by:

• Removing the substance, or replacing it with something safer.
• Enclosing the process, or using local exhaust ventilation to remove dust and fumes at source.
• Reducing the number of people exposed, and the time they are exposed.
• Providing personal protective equipment, such as gloves, goggles and respirators, as the last resort.
• Health surveillance, where it is required.

Employers have clear duties for hazardous substances. They must avoid or minimise exposure, carry out risk assessments for the substances in use, and put control measures in place to reduce the risks. PPE is used only as a last resort, when engineering controls are not practicable, and control measures must be reviewed and updated regularly. Workers who handle hazardous substances must be given training, instruction and information.

Where exposure cannot be avoided entirely, a hierarchy of control applies. First, design and use suitable work processes, systems, engineering controls, equipment and materials to minimise the hazard. Second, control exposure at the source, for example with adequate ventilation and extraction. Third, provide suitable PPE such as respiratory protection or protective clothing when no other measure is possible. Particular hazards such as asbestos or lead have their own specific regulations, and specialist training may be needed.

• Every hazardous chemical comes with a safety data sheet, explaining its hazards, safe handling, storage, first aid and spillage procedures.
• Labels carry hazard pictograms: a red-bordered diamond with a black symbol, such as a flame, a skull and crossbones, or a corrosive hand.
• Never transfer chemicals into unlabelled or food and drink containers, and never mix chemicals.
• Employees must be trained in the substances they use, the controls, and what to do in an emergency.

To reduce the risks from hazardous substances, employees should be trained and informed about several things. These are the substances they work with, including their names, the health risks they carry and access to their safety data sheets. They should know the exposure limits for substances and the health risks of exceeding them, and the key findings of risk assessments, exposure monitoring and health surveillance.

They must know how to apply the control measures correctly, how to report any deficiencies in those controls, and what emergency procedures to follow. Employees should also learn the safety signs used for hazardous substances. Examples are signs for irritants, which can cause rashes or redness, for flammable substances, which ignite when exposed to sparks, heat or flames, for toxic substances, which can have life-threatening effects even after brief exposure, and for oxidising substances, which can burn without air or intensify fires.

Working at height means work in any place where a person could fall a distance and be injured, even from a low height. It includes:

• Working on ladders, stepladders, scaffolds and mobile towers.
• Working on roofs, or near edges, openings and fragile surfaces.
• Working on the back of a lorry, or at ground level next to an excavation.

In Great Britain, work at height is covered by the Work at Height Regulations 2005.

Falls from height are a leading cause of fatal and serious injury at work. Work at height means work in any place where a person could be injured by a fall if no precautions were taken. It includes tasks at ground level as well as elevated ones. Examples are using a ladder to reach high shelves, working on a fragile roof that could collapse, and risks such as falling into a trench or excavation or through an opening in the floor.

The regulations cover many activities in every sector, including working on or reaching fragile roofs, such as asbestos cement or glass skylights, using ladders and stepladders, working on scaffolds and platforms, operating cherry pickers, working on the back of lorries or trailers, and working near edges, openings or holes. Your own duties include following training, reporting hazards immediately, using safety devices as instructed, using ladders only when safer alternatives are unavailable, and keeping three points of contact.

Employers must plan, supervise and carry out work at height safely, by people who are competent. They must follow this order:

• Avoid work at height where possible, for example by using long-handled tools from the ground.
• Where it cannot be avoided, prevent falls, using a safe existing place of work or equipment such as guardrails, scaffolds and work platforms.
• Where falls cannot be prevented, minimise the distance and consequences of a fall, for example with nets or fall-arrest harnesses.

Collective protection, which protects everyone, comes before personal protection. Employers must also plan for emergencies and rescue.

Employers must deal with work at height in a set order. First, where it is feasible, avoid the need to work at height at all, for instance by using extension poles to clean windows instead of ladders. Make sure everyone who works at height is trained and supervised. Choose work equipment that prevents falls, such as guardrails, and only use equipment that reduces the consequences of a fall, such as safety nets, if prevention is not possible.

Make sure all equipment is suitable, stable and strong enough for the task, inspect and maintain it regularly and replace it when needed. Provide protective equipment such as safety harnesses where falls cannot be prevented, and measures against falling objects. Consider the safety of the work environment, including weather, and plan and communicate emergency and rescue procedures to everyone involved. All work at height must be risk assessed, considering conditions, fall distances, frequency, rescue and equipment suitability.

• Mobile towers must be erected only by trained people, following the manufacturer’s instructions, with guardrails and toe boards fitted.
• Lock the wheels before climbing, and never move a tower with anyone on it.
• Mobile elevating work platforms, or MEWPs, must only be operated by trained people, on firm level ground, with a harness and short lanyard where required.
• Check for overhead hazards, such as power lines, before use.

Several rules apply when using mobile towers. People who build them must be trained in safe assembly. All the parts needed, including guardrails, toe boards and any stabilisers or outriggers, must be on site and the instructions available. The base must rest on firm, level ground with locked castors or properly supported base plates, never on bricks or building blocks. Fit stabilisers as the manual recommends, build only to the height the manufacturer specifies, and put edge protection on all access and working platforms.

Never use a tower in strong wind, or with damaged, missing or incompatible parts, and never move it with people or materials on it. When using mobile elevating work platforms, consider the height of the task, ground conditions and the risk of tipping, and operator training. Also consider collisions with steelwork, branches or power lines, crushing against ceilings, the need for harnesses, and daily visual checks.

Ladders and stepladders should only be used for short, low-risk tasks, where other equipment is not justified. A common guide is no more than 30 minutes in one position.

• Check the ladder before use, and do not use it if it is damaged.
• Place it on firm, level ground, at an angle of about one unit out for every four units up.
• Make sure it extends about one metre above the landing point, and is secured.
• Keep three points of contact, and do not overreach. Keep your belt buckle within the stiles.

Ladders should only be used when a risk assessment shows that safer equipment is not practicable. Today, low-level access platforms and podium steps remove the need for ladders in most tasks. There are two conditions. Ladders are only for low-risk tasks, and use should not exceed 30 minutes. Secure the ladder at the top or bottom, or use a stability device, and in exceptional cases a second person may foot it.

Place it on a stable, level, non-slip surface, never on pallets or loose stones. Position it at 75 degrees, one unit out for every four up, with the top against solid support rather than plastic guttering. Keep three points of contact, avoid overreaching with your belt buckle inside the stiles, and never work from the top three rungs of a leaning ladder. Use a tool belt, avoid strong wind and extreme cold, and inspect the feet, stiles and rungs before each use. Stepladders follow similar rules, and should face the work.