Shaping up on laser safety

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Many university laboratories using lasers have had to shut down temporarily following a visit from an HSE inspector

Matthew Dale learns how the safety knowledge of the laser community is not yet fully up to scratch

When I sat down to talk with one of the UK’s biggest names in laser safety, Professor John Tyrer, of Loughborough University, I wasn’t prepared for what I was about to learn over the next hour.

As a frequent chair of the Laser Institute of America’s International Laser Safety Conference (ILSC), and a provider of laser safety training for 25 years, I thought I would hear that the perception and understanding of laser safety has generally improved throughout Tyrer’s career. How very wrong I was.

What he instead planned to reveal was a daunting, mostly unchanging lack of awareness of the hazards that currently exists. This spans from the individuals working with lasers or advising about laser safety in manufacturing facilities, hospitals or university departments, to entire companies manufacturing and supplying the lasers themselves.

Our conversation began after Tyrer had just finished speaking with a blue chip company that had recently bought a laser from a large UK manufacturer. The advice given was that the system was completely safe to use while closed up in its casing. Should the company wish to open it up, for example to perform alignment procedures, a pair of goggles must be worn. However, the laser system in question was capable of burning skin and singeing hair, as well as damaging the eyes.

‘The blue-chip company challenged the laser manufacturer on this, saying that telling them to “just put on a pair of goggles” is totally unacceptable and does not align with the way the world works now regarding safety,’ said Tyrer. ‘However, the laser company insisted it was fine and that this was how things had been done for many years.’

This happened because the perception of laser safety has not really changed in the last 40 years. Consequently, protection strategies are still dominated with the usage of goggles, according to Tyrer. He himself has also seen laser companies claiming that eye protection was all that was needed when working with fibre lasers of at least a kilowatt in power, which are more than capable of damaging skin and hair. ‘This is wrong, you need a full protective suit that protects the skin, as well as the eyes,’ he said. ‘But the laser firms don’t always recommend that, they’ll just point you towards a pair of goggles. It’s sometimes as if no-one has ever thought what happens when the laser radiation actually escapes!

Monsters in the closet

Another cause for concern regarding modern perception of laser safety is the ‘fortress approach’ many firms have chosen to adopt when purchasing laser technology, Tyrer continued.

‘Due to the direct optical radiation hazard dominating the laser safety scene, many people believe they’ll be completely safe if they contain their laser system within an enclosure or an entire room, securing it with an interlock mechanism that shuts off the laser as soon as someone enters,’ he said. ‘When such a “fortress” is installed, it is normal for a firm’s employees to assume that all the safety matters pertaining to the new laser have been dealt with, and that the guarding provided by the laser safety officer takes into account all known hazards. The occupants of these fortresses then mistakenly believe that they are safe. However, unfortunately within these enclosures live many terrible monsters which can kill unsuspecting intruders.’

Tyrer noted that despite being the most prominent hazard when working with lasers, no-one in the UK is yet to die from being hit by a laser beam. Instead, 150 people in the country have died since records began from fires that have been ignited by a laser beam, and at least 50 people die each year from cancers and respiratory diseases caused by the inhalation of breakdown products from laser processing.

It was Tyrer himself who started working with the UK’s Health and Safety Laboratory (HSL) many years ago to conduct laser fume diagnostics and determine the dangers they pose when inhaled.

The laser fumes released during surgery can be fatal if not extracted properly.

‘Let me give you an example,’ he said. ‘When you process stainless steel with a laser, its chromium and nickel components are released as microscopic particles. If inhaled, these fumes can kill you – not instantly, but in 10 to 20 years’ time, and in a very nasty way.’

Not just metals, but plastics and biological tissues also release harmful fumes when processed with a laser. Even viruses can be released into the atmosphere if, for example, an infected patient has some form of laser surgery, such as hair or tattoo removal.

‘And it is in these fortresses, in hospitals, universities and manufacturing facilities, where people think they’re safe,’ said Tyrer. ‘The laser safety officer will have said that they’ve taken into account proper fume extraction, but this often means they’ve just put big extractor fans in the ceiling. All that does is drag the air out, rather than dealing with the harmful fumes themselves – does a kitchen extraction fan remove all the smells when you’re cooking? No! The principle is the same with fume extraction in laser processing. Dedicated laser fume extraction systems are needed that remove all the microscopic particles from the air.’

An inspector calls

Over the years Tyrer has worked closely with the UK’s Health and Safety Executive (HSE), and with them has identified laser generated fumes as a new workplace hazard, especially in schools, where CNC laser cutters are frequently used by children for design & technology projects.

And so, for the past few years, the HSE has been sending its inspectors far and wide across the country to ensure that the proper laser safety precautions are being taken – including both proper fume extraction and PPE usage in academic facilities.

‘The HSE has begun its inspections at the universities (which in turn would influence the secondary schools) and it’s been finding a considerable number of laser safety issues, said Tyrer. ‘Even the largest and best universities in the UK have had to shut down and modify a number of laboratories where a laser is being used, and this wasn’t just one or two.’

Loughborough University was one of the first to be on the receiving end of such an HSE inspection, Tyrer noted, the experience of which has been documented in a paper1 he presented at ILSC last year.

Since the HSE began conducting these rigorous laser safety inspections, other European countries have followed suit, according to Tyrer. ‘There’s been a cascade of countries’ HSE departments now doing it,’ he confirmed.

What needs to change?

Tyrer revealed that unfortunately there are still many laser safety advisors out there telling people that a pair of goggles will be adequate when working with lasers capable of harming the skin as well as the eyes.

This, and the reason why many safety ‘fortresses’ are being constructed that don’t account for all the hazards of laser usage, is because many individuals involved in laser safety generally come from a technical laser background, and as such their knowledge is specific to the dangers of laser radiation, rather than having a broad understanding of general safety competence.

‘In order to avoid the building of such fatal facilities within an organisation, it is necessary that laser specialists attain general safety competence, and this is different from training,’ Tyrer emphasised. ‘Most laser safety standards are written by subject-specific laser specialists and in some circumstances fail to appreciate the broader safety regulatory framework. There are even several examples where advice given in laser safety standards is in direct contravention of the national safety regulatory framework.’ 

He explained that by having a more comprehensive awareness of general safety, laser specialists will have a much broader view and attitude towards the hazards presented by laser systems. This would allow them to perform an all-hazards-based risk analysis of their entire laser system, as opposed to a hazard analysis dominated by the problems caused by laser radiation.

Reference

[1] ILSC 2019 Paper 1103: Being on the receiving end of a government laser safety inspectors formal laboratories inspection - John Tyrer: https://doi.org/10.2351/1.5118533

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