Plant special: Biting the dust | New Civil Engineer

Contractors are putting the long-term health of their employees at serious risk by using tools not fitted with adequate dust suppression systems. Margo Cole reports.

The health hazards of breathing in asbestos dust are now fairly well accepted within the construction industry, but asbestos is not the only substance that produces dust that can kill.

Any activity that involves cutting, grinding or drilling concrete or stone can produce respirable crystalline silica (RCS) − known as silica dust − which has been linked to lung cancer, chronic obstructive pulmonary disease (COPD) and silicosis.

Trade union Unite estimates that several hundred thousand workers in the construction industry could be exposed to silica dust on an occasional basis, and about 140,000 workers exposed to it more regularly.

“Silica particles are very small, so they get breathed very deep into the lungs,” explains Health & Safety Executive (HSE) respiratory disease project manager Robert Ellis. “The dust comes from concrete or stone, which is why it’s so dangerous, because people who are cutting everyday materials are at risk. You don’t associate a lump of concrete or stone, or the dust that comes off it, with cancer.”

“People cutting everyday materials are at risk. You don’t associate a lump of concrete or stone with cancer”

Robert Ellis, HSE

Ellis estimates that more than 500 construction workers a year die of lung cancer, while thousands develop silicosis and COPD. RCS is a major factor, as the dust particles are so fine they often go unseen. “If you can’t see it, why would anybody think they’re at risk to their health?” says Ellis.

“But you only need to inhale a very small amount of it each day to give you lung disease,” he continues.

Stefan Geisse, marketing manager for corporate health, safety and environment at tool manufacturer Hilti agrees.

“Dust exposure depends on many factors like the application, base material, consumable, system being used, working time, operator technique, room size, and ventilation. It seems obvious that applications like cutting, slitting, grinding or chiseling are very dust intense. But also dust that is not visible can be dangerous.”

Silicosis − also known as Potter’s Rot − occurs when the RCS causes inflammation and scarring of the lungs. It can result in shortness of breath, cough, fever, and the skin taking on a bluish tinge. COPD is the generic name for a group of lung diseases like bronchitis and emphysema, which results in severe breathlessness and prolonged coughing.

Ellis claims that thousands of construction workers may contract silicosis and COPD as a result of breathing in silica dust but they often go unnoticed because they are slow, progressive and usually take some years to develop. The effects are also irreversible.

Jobs involving cutting or drilling are dust intensive

“People who get these diseases leave the industry then quietly suffer and die,” says Ellis. “From the age of 40 they might be getting a bit of a cough and feel uncomfortable at night. Then into their 50s they could be suffering of sleep because they can’t breathe properly.

“By their 60s they can’t do any sport or run for the bus. It’s a long latency disease − just when people are looking forward to retirement is when they’re going to be hit. The worst cases are wheelchair-bound and on bottled oxygen.”

Exposure to silica dust is covered by the Control of Substances Hazardous to Health (COSHH) regulations, which set out the steps employers should be taking to protect their workforce. In 2006 the Health & Safety Commission (HSC) set a new workplace exposure limit for RCS of 0.1mg/m3. This could be just five or 10 minutes of sawing, cutting or grinding a day, although the HSE has shown that a saw touching a concrete kerb for just five seconds generates enough RCS to reach the daily exposure limit if it was all inhaled.

Workers can be protected from exposure by a variety of means, including dust suppression, usually with water, dust extraction, and wearing appropriate protective equipment, including a respirator. One of the biggest problems with RCS, however, is that it not only affects the operatives who are using the cutting equipment, but also anyone working in the vicinity, or even members of the public.

“Productivity losses and increasing costs due to bad health and safety practices on sites can’t be ignored”

Stefan Geisse, Hilti

“There’s no doubt that RCS is a killer,” says Hire Association Europe (HAE) technical services manager Richard Carter, “and it’s something that doesn’t just kill the operative, it can also pose a serious risk to bystanders.”

Carter says that HAE members, which include the UK’s top equipment hire companies, have little control or duty of care over what a customer does with the equipment that is offered to them. “Our duty of care ends with the offer of appropriate PPE,” he adds.

The biggest problem, especially in these recession-hit times, is that dust suppression or extraction equipment adds to the cost of hiring or buying a cutting or drilling tool. Although there has been an increase in the number of cut-off saws being hired out in the last two or three years, the number of water suppression bottles that have gone out with them has not gone up. The bottles can add up to 30% to the hire cost.

“Hire companies can’t afford to give out this equipment without charging for it,” says Carter. “But what happens is the contractor just comes in and hires the tool and doesn’t take it [the suppression/extraction equipment].

“Manufacturers really have put a lot of time and effort and money into developing ventilation, water suppression and dust extraction systems, but you can’t force people to use them.”

One of those manufacturers is Hilti. It has developed a dust removal system in which some of its most popular tools, including diamond cutters, rotary hammers, chasing tools and grinders, are designed to plug into a vacuum cleaner that can remove up to 99% of the RCS.

Jobs where exposure to silica dust is a significant risk

● Drilling in a poorly ventilatedundercroft

● Drilling into brickwork under an arch blocked at one end

● Chasing out cracks in a screeded cement floor in a large open indoor are

● Chasing out mortar between bricks prior to re-pointing

● Cutting paving kerbs in an open area

● Cutting blue brick

● Cutting breeze block

● Cutting window openings in a concrete wall with a wall saw or cutting concrete with a floor saw

● Rubble clearance and removal

● Concrete crushing from a demolition job

“We are aware that construction is one of the unhealthiest industries and that health and safety issues not only damage people but also are essential for our customers from an economic perspective,” says Geisse.

“Productivity losses and increasing costs due to bad health and safety on sites are tremendous and can’t be ignored.”

In 2007 the European Agency for Safety& Health at Work estimated that the European construction market was worth €902bn (£817bn) a year, but said that accident and ill-health costs in the sector accounted for 8.5% of project costs − €75bn (£68bn) each year. “It is vital that we work hard on providing health and safety solutions to our customers,” says Geisse.

Eliminating dust not only has the potential to save lives, but also to improve efficiency on site. “Dust can negatively influence work progress and productivity.

“For example, the jobsite must be sealed (especially at renovation projects), additional breaks are needed, the lifetime of tools and consumables is shortened and additional labour time is required for cleaning the jobsite.”

“There’s no doubt RCS is a killer. It’s something that doesn’t just kill the operative, it can also pose a serious risk to bystanders.”

Richard Carter, HAE

Hilti claims that the economic argument against using dust suppression or extraction equipment − that it costs more to hire − is too short term a view. Over time, the firm says, tools last longer because they are not being clogged, and work can be done much quicker.

So even though the initial cost is higher, running costs are lower as downtime for repairs and cleaning is reduced and productivity goes up.

It is an argument that needs to be accepted by contractors if, as the HAE’s Carter says, market forces currently dictate whether they take up the offer of dust reduction kit when they hire cutting and grinding tools.

The alternatives could be more costly: being hit by an HSE fine or, worse, waiting for the law suits to roll in from lung cancer and silicosis sufferers and their families.

The HSE is upping enforcement for RCS exposure, and last year took a quarry company to court for breaching the COSHH regulations by failing to ensure employees’ exposure to RCS was adequately controlled. The firm was fined £3,750 and ordered to pay costs of over £8,000.

Prosecution followed a routine, unannounced inspection in which the HSE discovered that an employee had contracted silicosis and that a number of others had been exposed to levels of RCS in excess of the workplace exposure limit.