Some work processes, notably pavement cleaning, can expose workers to pathogens and the risks of diseases associated with animals. Neelum Sanderson and Professor Anne Harriss assess best practice around risk management of pavement cleansing processes and possible exposure to pathogens within dog excrement.
Workers in a variety of settings may be exposed to hazards associated with their work tasks. In addition to physical or chemical hazards, some work processes may also expose employees to pathogens and risks of diseases resulting from pathogens associated with animals, zoonoses, and transmitted to people.
This article explores some of the considerations to be made with regards to employees undertaking street cleaning duties that expose them to microbes within dog excrement.
About the authors
Neelum Sanderson is a specialist occupational health nurse and Professor Anne Harriss is emeritus professor in occupational health
All managers must ensure that workplace hazards are identified and effective control measures are put into place in order effectively to manage health and safety and ensure compliance with the Health and Safety at Work etc Act (1974) and the Management of Health and Safety at Work Regulations (1999).
The newly appointed manager of a local authority street cleansing team (we’ll call him Richard) was in the process of updating the departmental risk assessments and sought advice from the occupational health service with regards to possible exposure to biohazards.
Richard recognised that all the departmental risk assessments for the work processes for which he was responsible must identify the hazards to which his employees might be exposed.
Once hazards have been identified, control measures must be put in place and their effectiveness evaluated. The risk assessment process involved consideration of the places where his team work, the processes they undertake, the materials they handle and the equipment which they used.
Richard had already considered a number of physical, ergonomic and chemical hazards to which his team might be exposed and was satisfied that the control measures for these hazards were effective.
He was now seeking occupational health (OH) advice regarding the possible exposure to dog excrement through the cleaning activities his team undertook.
He was aware that the Control of Substances Hazardous to Health Regulations (2002) are applicable to work processes that expose workers to dog excrement because of the risk of exposure to micro-organisations with pathological effects.
Potential health ill-effects of exposure to dog excrement
Dog excrement is a recognised source of pathogens. Without safe systems of work and appropriate personal protective equipment, those employed on street cleaning processes may become exposed to, and infected with micro-organisms with the potential to result in unpleasant, possibly serious health effects.
Several micro-organisms are found within the gastro-intestinal tract of dogs. They include the parasitic roundworm, Toxocara Canis (Cinquepalmi, Monno, Fumarola and others. 2013), protozoa including Giardia (Ballweber, Xiao, Bowman D and others, 2010) and Cryptosporidium (Raza, Rand, Qamar and others 2018).
A multitude of bacteria are also present including Escherichia coli which is usually referred to as E. Coli. As Dambourg et al (2015) note, E. Coli is increasingly found in dog faeces. As all these pathogens are transmitted via a faecal-oral route, control measures for one of these pathogens will be an effective control measure for them all.
As local bylaws require dog owners to remove and dispose of their dogs’ faecal deposits, many deposits on pavements are left by strays. Clinically relevant, and in some cases, antibiotic-resistant bacteria can be transmitted to people as a result of direct exposure or via environmental contamination.
In the context of street cleaning operations, the maintenance of high standards of personal and general hygiene reduces the risk of transmission of these organisms to workers. Regular hand washing is essential, particularly after handling any equipment that may have become contaminated by faecal material, and before eating meals or snacks.
Integral to the risk assessments required by law is the recognition that exposure to these bio-hazards is a significant risk and acknowledgement that it is essential that work practices should minimise the risk.
There is the potential for street cleaners to become infected by any of these pathogens, should high levels of personal hygiene not be maintained. Pathogen transfer may occur when cleaning street surfaces and when disposing of dog excrement, a particular concern as infection by these organisms can lead to illnesses including diarrhoea and vomiting.
Toxocara canis has the potential to affect a range of organs, including the liver, lungs, eyes and brain. The associated clinical features are diverse and debilitating. They include fatigue, appetite and weight loss, skin rashes, dyspnoea and seizures. Should the eyes be affected there may be visual disturbances and there is a chance that there will be permanent loss of vision (NHS Choices 2015).
Assessment and control of occupational risk
As Richard had requested advice regarding how to manage biological hazards, a workplace visit was undertaken by the OHA. The purpose of this was to observe the job tasks, working practices and methods of collection and disposal of excrement.
This knowledge ensured that the most appropriate occupational health advice could be given. This visit provided opportunities to ascertain the processes involved in the collection and disposal of dog excrement.
The observed work tasks included those that involved the removal collection of faecal deposits from pavements. The team collected deposits using shovels then transferred material from the shovels directly into disposal bags. The floor surface was then cleaned with commercial cleaning agents.
Pavements were cleaned with a solution of bleach that had been diluted to a ratio of one part of bleach in 32 parts of water. The bleach, once diluted, was decanted into large spray bottles and sprayed on to the affected areas.
Following this, the pavements were cleaned using the standard method used by the local authority. This was dependent on the surface areas and ranged from the large carts covering large areas to smaller ride on machines. Neither process was identified as producing aerosolised materials.
The team wore gloves to protect their hands from the diluted bleach and a mask for eye protection; the personal protection equipment (PPE) was well tolerated by the team with no issues verbalised.
The PPE was selected from the material safety data sheet (MSDS) provided by the company producing the bleach; this information also contained information on how to best dilute the product to get the most effective result. The MSDS was stored electronically to allow ease of access should an incident occur.
The bags containing the dog excrement were then double bagged, with the first tied and the second, impervious outer bag being further sealed. These filled bags were then stored in the rear of the work vehicle until returned to the depot.
At this point the bags containing the excrement were unloaded and deposited via the local council’s waste depot in the general household waste area. The preference is that the bags are double wrapped to protect their workers and also to prevent smells prior. The final destination for the bags is land fill, hence the importance of ensuring the bags are bio- degradable.
It became apparent that members of the cleansing team routinely took their meal breaks in their work van, with workers observing that this “saved time”. Eating meals in the work vehicle poses a significant risk of cross-contamination, as this vehicle was being used to transport bags of faecal matter, contaminated work equipment and personal protective equipment, including overalls, work boots and protective gloves.
As this put the team at risk, it was a source of significant concern. Furthermore, cleaning materials were also generally transported and stored in this work vehicle. This put team members at significant risk of contracting work-related infections and health effects in the event of spills of cleaning chemicals.
Following an initial evaluation of the risk of contamination followed by possible risks to health, the next stage of the process was deciding on, then implementing where possible, further control strategies that are designed to reduce the degree of risk associated with work tasks.
At best, hazards should be completely negated; if this is not possible the degree or risk should be reduced as far as reasonably practical.
The team were provided with personal protective clothing, including overalls, safety boots and disposable gloves. Working predominantly “on the road” with limited access to welfare facilities resulted in staff finding it very difficult to maintain high levels of personal hygiene. Furthermore, the meal breaks in the back of the work vehicle were a clear infection control risk, increasing the risk of workers contracting one or more pathogens as a consequence of their work tasks. Exposure to biological hazards was highly likely as a result of the work processes of the cleansing team. Existing control measures were considered to be inadequate.
The Management of Health and Safety at Work Regulations (2006) requires employers to provide appropriate welfare facilities including: access to drinking water and as they must wear special clothing, changing areas are required.
The nature of the work processes the team undertook made this difficult. All employees should have access to facilities to store their overalls and personal clothes; toilets with hand basins equipped with soap and hand drying facilities; drinking water. This was difficult whilst on the road.
Guidance and recommendations
The following issues were highlighted to Richard:
1) Automating the pavement cleansing process would be preferable to the current manual cleansing processes. If the associated costs initially preclude such an initiative, budgeting for this should be a medium-term strategy.
Until these street cleansing processes can be mechanised, it was essential that effective infection control measures should be established with due regard for the work processes and associated job tasks linked with the use of personal protective equipment.
2) There should be urgent attention to personal and work area hygiene. Of particular public health concern was the current practice of taking meal breaks in the rear of the work vehicle, in close proximity to bags of dog excrement and contaminated tools (and see point four).
3) Supply of PPE. With regards to PPE, a supply of clean dry overalls and disposable protective gloves should be available for use when undertaking processes involving possible exposure to dog excrement.
Team members should be taught the correct method of removing and donning of gloves reducing the risk of further hand contamination. Once gloves have been removed, workers’ hands should be thoroughly cleaned with hand wipes then alcohol gel applied to all surfaces of the hands and wrist, paying particular attention to the area between the fingers.
On return to the depot workers should then wash their hands thoroughly with soap and hot water and conditioning creams applied. All workers employed on street cleansing processes should be issued a supply of clean, dry work overalls daily.
Dirty overalls should be laundered on a high temperature wash. Wearing clean overalls daily is more hygienic than re-wearing contaminated work wear and negates the need to store contaminated work clothes in their work vehicles.
4) Team members taking their meals in the work van should be discontinued with immediate effect, as this was a poor infection control practice. Work tasks should be planned in such a way that the team were able to return to their depot to take meal breaks.
This would facilitate team members being able to remove their overalls and access hand-washing facilities before they ate their meals. They would then be able to eat in an appropriate clean environment rather than in work vehicles.
In the short term, should it not be possible to plan work in this way, workers should at least be reminded to remove their work clothes and apply anti-bacterial hand cleansing gels prior to eating or drinking (WHO 2009).
5) Infection control “toolbox talks” should be developed. These would inform the team of the biological risks of their work and should be delivered to all members of the cleansing team.
These approaches should explore approaches to maintaining their personal, general and food hygiene, particularly in relation when taking meals.
The importance of changing their work overalls daily, or when contaminated, and the correct process for donning, removing and disposing of gloves should be explored within these taking part.
6) Consider vaccination. Many employees are exposed to hazards and risks. Vaccinations can provide protection against some of these. Under the Health and Safety at Work Act 1974 and the Management of Health and Safety at Work Regulations 1999 the employer has a legal duty to protect the health of the employees.
It is a requirement of Regulation 6 of the Control of Substances Hazardous to Health (COSHH) Regulations 2002 for employers to assess the risk to employees of exposure to such microbial hazards which may cause ill health.
In the case of these street cleaning processes, the control measures were evaluated as was the severity of the illness should infection occur.
It was recommended that those working in the street cleaning teams should be offered the following additional immunisation:
- Tetanus – every 10 years, no more than three vaccinations needed in a lifetime.
- Hepatitis A – a single dose followed by a booster dose at six-12 months. The booster will give immunity beyond 20 years.
- Influenza – one vaccine per year; the optimum time for influenza vaccination is late September to early December.
In summary, this article covers the process and considerations needed to be made when assessing how to manage biological hazards in the workplace, in this instance dog faeces, and how this exposure could affect employees.
By completing the risk assessment process, each element of the work practice was assessed in some details and areas where risk could be reduced was highlighted and measures implemented.
Richard, the manager, with the assistance of his occupational health service was able to utilise the health and safety legislation to provide a framework and guidance on how to assess, manage and review the risks associated with this work practice.
Ballweber L, Xiao L, Bowman D, Kahn G, Cama VA (2010). “Giardiasis in dogs and cats: update on epidemiology and public health significance”. External Trends Parasitol. 2010;26(4):180-9.
Cinquepalmi V, Monno R, Fumarola et al (2012). “Environmental Contamination by Dog’s Faeces: A Public Health Problem”. Int J Environ Res Public Health: Jan; 10(1): 72-84.
Dambourg et al (2015). CTX-M-1 and CTX-M-15-producing Escherichia coli in dog faeces from public gardens. Acta Veterinaria Scandinavica 57(8). Available from https://actavetscand.biomedcentral.com/articles/10.1186/s13028-015-0174-3
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WHO (2009). “Guidelines on Hand Hygiene in Health Care”. Available at: http://apps.who.int/medicinedocs/documents/s16320e/s16320e.pdf