Wellbeing: Toxic fumes

There are significant health hazards associated with installations, maintenance and refurbishments. Some tasks generate or involve toxic fumes that pose a threat to health, including respiratory distress, poisoning and even death.

In addition to toxic fumes from chemicals or gas from sewers, there are also dangers associated with pipework.

Sewer gases

Although modern plumbing systems have measures in place to protect buildings from sewer gas leakage, engineers may be called out to deal with unpleasant smells.

Sewer gas is a by-product of the breakdown of human waste. It comprises a mixture of gases, including hydrogen sulphide, ammonia, methane and carbon dioxide. Hydrogen sulphide is what creates the rotten egg smell. In most cases, leaks are caused by plumbing system failures, such as cracked pipes, blocked air vents, clogged drains, dry plumbing or loose toilets. Although sewer gas isn’t necessarily toxic at low levels, higher levels of exposure can cause symptoms of sewer gas poisoning, such as respiratory irritation and eye damage. Not only that, the gas is also a fire hazard.

Symptoms of exposure to sewer gas include fatigue, headaches, nausea, dizziness and poor memory. High levels of exposure can cause loss of smell, mouth, throat and lung irritation, eye irritation, seizures, coma and death. Exposure to higher levels of sewer gas requires immediate medical attention. To mitigate these risks, engineers must use personal protective equipment (PPE) and respiratory protective equipment (RPE) and ensure proper ventilation.

Full-face shields or respirators, chemical-resistant goggles, elbow-length waterproof gloves and liquid-repellent coveralls or protective work wear are essential.

Soldering fumes

According to the Water Supply (Water Fittings) Regulations 1999, plumbers must use lead-free solder for drinking water pipes, such as those made from tin-copper or tin-silver-copper alloys. However, lead solder can be used for non-drinking water systems, such as central heating.

The fumes given off by welding comprise a mixture of airborne gases and very fine particles, which can cause pneumonia, asthma, metal fume fever, throat and lung irritation, and reduced lung function if inhaled. Exposure to some welding fumes and gases can cause pulmonary oedema and lung and nasal cancers.

Lead-free solder fumes can also be toxic, primarily because prolonged exposure to the fumes from the flux and heated metal particles can cause respiratory irritation and other health problems. While lead-free solder eliminates the risk of lead poisoning, the process often requires higher temperatures, creating more fine metal oxide particles and requiring the use of more aggressive chemicals in the flux.

When working where lead is present, installers should use RPE such as face masks, hoods and helmets. The type of respirator will depend on the amount of lead present and the job.

CIPHE guidance states employers must train staff in how to properly fit, clean, maintain and use RPE, and provide refresher courses to ensure this training is up to date. Self-employed engineers should also carry out this training. Tests need to be carried out to make sure face masks fit properly (it is an employer’s duty to make sure employees have a face fit test before using any kind of respirator) because if you have a beard or stubble, wear glasses or have sideburns, certain respirators may not fit adequately.

For more information on lead poisoning, visit: ciphe.org.uk/public/plumbi...

Welding fume control

The Control of Substances Hazardous to Health (COSHH) Regulations 2002 require employers to ensure that exposure is prevented or, where this is not reasonably practicable, adequately controlled. This guidance advises how this can be achieved by applying the principles of good practice: hse.gov.uk/pubns/guidance/...