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Safeguard OSH Solutions - Thomson Reuters

Safeguard OSH Solutions - Thomson Reuters

Safeguard Magazine

Look & Learn—Simply complex

Occupational hygienist MIKE GRAY takes a phone call which requires diplomacy, persuasion, insight, and – ultimately – leads to a simple solution.

This is a call we had that will sound all too familiar to many an occupational hygienist. “Our staff operating the bag machine are complaining of sore eyes and headaches. We need you to air monitor for formaldehyde, when can you get here and how much?”

“Why do you want formaldehyde monitoring?”

“Because that’s what the last person we called in did.”

The bag machine takes a thin polyethylene plastic tube from a roll, a hot wire cuts it to length (sealing the end in the process), and stacks the newly formed bags for the operator to collect. The operator stands by the exit end of the machine to remove the stacked bags and fix the frequent product jams that occur.

Wire cutting polyethylene can generate smoke containing hydrocarbon oil and waxes, partly oxidised hydrocarbon (aldehydes and organic acids), and carbon monoxide – all totalling perhaps hundreds of compounds at trace levels and each one, individually, well below the Workplace Exposure Standard.

So why was formaldehyde chosen by the last consultant? I suspect because they were a research company developing a new air monitoring instrument, the instrument detects only certain gases and vapours including formaldehyde, and their core purpose is to develop the instrumentation and not to carry out occupational hygiene investigations.

The next half-hour on the phone involved talking the client around to a new way of looking at the problem. This involved proposing air testing for oil mist as an indicator of fume levels for use in assessing remediation effectiveness during future monitoring. (Air testing was expected by staff and management, and the smoke will contain particulate, wax and hydrocarbon oil.)

This is one of those rare occasions when we monitor without a standard against which we can compare the results. More importantly, we recommended that the assessment should include an evaluation of the fume extraction system on the machine. Convincing the client not to monitor for formaldehyde required a perhaps subconscious acceptance on their part that the consulting fee previously paid may have been wasted money. Eventually the client was prepared to humour us with our investigative approach.

A couple of days later we were placing a small lightweight air sampling pump on the operator’s waist belt leading to a sampler on the lapel, right next to the breathing zone. Over the next two to three hours we would collect an air sample mirroring what the operator herself was breathing during a typical continual use period of the machine.

On our return to remove the sampler, we began the fume extraction system assessment. With the machine in standby, by using smoke tubes we observed that the fume extractor was working effectively, removing all fume from the process. However when the machine was in operation each formed bag acted like a large paddle wheel, fanning smoke and fume out into the operator’s breathing zone.

Out came the trusty Stanley knife and duct tape and in short order three 100mm strips of corrugated cardboard had been taped to the extraction hood. Further smoke tube testing of air flow showed that the fume was now being effectively collected and directed up a duct and out of the building. All that was needed was for the plant engineer to effect the modifications using Perspex, and to repair a sealing strip that was also observed to be leaking fume, and so the problem was solved. If required a further air test would be able to provide a measure of the effectiveness of the remediation.

You might say this is not brain surgery and you would be quite right. This is an example of a relatively simple but common type of industrial fume problem that occupational hygienists are regularly called in to solve. The skill is in assessing the problem with a knowledge of chemistry process, looking at the problem with new eyes, not being swayed by the client’s preconceptions, and being able to see the simplicity in a complex problem so that it can be measured and fixed. That’s what a good occupational hygienist can provide you with.

So what can readers take from this? I would suggest consideration should be given to including an occupational hygienist as part of your safety team to be available for selected safety meetings and during workplace walkthrough hazard assessments. This may only require a couple of chargeable hours per month (provided detailed reporting is not required).

An experienced occupational hygienist will be familiar with systems and procedures used in many industries, which, together with their knowledge of chemical and process fume management and control will provide a valuable addition to your safety team. This fresh pair of eyes can often see problems that are difficult to see for those intimately involved on a daily basis with a work station under assessment.

Occupational hygiene has now come of age in New Zealand. The NZ Occupational Hygiene Society is experiencing rapid growth, and there are signs of a health and safety governance revamp in the air for New Zealand. It is to be hoped that these developments will lead to the decline and disappearance of some of the poor air quality and chemical handling nightmares that are still accepted by some businesses.

MIKE GRAY is managing director of consultancy firm Chemsafety.

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