Reduction of work accidents through the implementation of containers for solid waste collection

Nailson Diniza, Tomi Zlatarb, Felipe Mendes da Cruzc, Béda Barkokébas Juniord, Eliane Lagoe aLaboratory of Occupational Safety and Hygiene, Polytechnic School of Pernambuco, University of Pernambuco, BR (nds_pec@poli.br) ORCID: 0000-0002-1575-2788. bLaboratory of Occupational Safety and Hygiene, Polytechnic School of Pernambuco, University of Pernambuco, BR (tomi.zlatar@poli.br) ORCID 0000-0002-8915-908X. cLaboratory of Occupational Safety and Hygiene, Polytechnic School of Pernambuco, University of Pernambuco, BR (felipemendeslsht@poli.br) ORCID 0000-0002-0163-465X. dLaboratory of Occupational Safety and Hygiene, University of Pernambuco, BR (beda.jr@upe.br) ORCID 0000-0003-3130-3277. eLaboratory of Occupational Safety and Hygiene, Polytechnic School of Pernambuco, University of Pernambuco, BR (eliane.lago@upe.br) ORCID 0000-0003-0987-3492.


INTRODUCTION
According to the Brazilian Association of Public Cleaning and Special Waste Companies (Abrelpe, 2017), Brazil annually generates 78.4 million tons of urban solid waste. In 2017, the Brazilian municipalities invested an average of R$ 10.37 per inhabitant per month in the urban cleaning service. Despite the financial crisis in Brazil, the resources movement in the sector corresponded to R$ 28.5 billion. The urban cleaning service consisted of 337 thousand formal jobs, where 59.1% of the produced waste was collected and destined to landfills, while additional waste was discarded inadequately. This shows that the urban cleaning sector still needs to grow in order to attend present necessities and that in the near future it will be necessary to apply more resources and hire new professionals.
In Brazil, there is a great difficulty to implement a unified urban cleaning system, considering that the country has a large extension and has developed unevenly, with most of the population concentrated in the coastal region, due to different topographies and infrastructures. It is possible to note cultural and income differences across different regions of the country. These variations had a direct influence on the methodology used for waste collection since the sites generate different types and amount of waste (Eigenheer 2009).
When solid waste is discharged inadequately, it can pose problems for the society, leading to the proliferation of rats, cockroaches, flies, among other disease vectors. It can also cause diseases among workers who have direct or indirect contact with wastes, such as, headaches and vomiting, by the odour, or contamination through the contact of the infected material. The employer is also affected when the solid waste is discharged in a defective manner, as improper storage raises the time required to collect waste (Diniz ET AL., 2018;National Secretary of Environmental Sanitation, 2008).
Nevertheless, occupational safety and health problems are not exclusive to Brazil. Worldwide, there have been several studies on work accidents and safety and health risk management. In Paraguay, a study conducted by Flores, Carvalho e Radon (2018) concluded that each year about 37.5% of collecting workers suffer work accident; which is in accordance with the data published by the Canadian Union of Public Employees (CUPE, 2010) showing a percentage of 35%; and in accordance with the data from Ethiopia showing a percentage of 34.3% of collecting workers suffering accidents every year (Eskezia ET AL., 2016). The Bureau of Labor Statistics (BLS) from USA (United States of America, 2017) show similar results, stating that the activities of waste collection and maintenance are one the top five services which were responsible for most accidents, with the risk for waste collectors being 10 times higher compared with the mean value from all other sectors in the USA.
In addition to all the mentioned problems, the occurrence of work-related accidents is common in the urban cleaning service. According to a study carried-out by Velloso, Santos, and Anjos (1997), 80% of the waste collectors suffered work accidents during the collection activity. Studies show that waste collection is one of the most dangerous activities with a high risk of exposure to sharp materials and bacteria's (Tibbetts, 2013). A study conducted in South Korea (Jeong, Lee, and Lee 2016) show that falls (including falls as a result of slips and falls from height) represent 42.4% of all analyzed accidents, while traffic accidents and represent 13.6%, musculoskeletal disorders result in 11.1%, while other types of accidents are accounted for 32.9%. Another study, carried-out by Diniz et al. (2019) pointed out that "Affected by object/tool", "Traffic", "Falls" and "Sharp materials" were the main causes of accidents among waste collectors, where "Sharp materials" represented more than 50% of major causes. One of the proposals brought by Diniz et al. (2019) was to carry out a study to verify if the implementation of communal waste containers built according to the standard (ABNT, 1993), would reduce the number of accidents resulting from urban cleaning. Therefore, the objective of this study was to analyze the leading causes of occupational accidents in the urban cleaning service and to verify if the implementation of containers would reduce the number of accidents.

MATERIALS AND METHODS
The study was subdivided into two phases. The main causes of accidents were identified in the first phase, while in the second phase was verified and analyzed the effect of the implementation of containers on major causes of accidents, as illustrated in Figure 1.

Identification of the causes of accidents
In order to identify the main causes of accidents, this study considered accident data from two large waste collecting companies (company A and B) operating in different Brazilian cities. The companies were subject to the same legislation and thus were obliged to offer the same conditions, having as main variable the number of workers. In total, this study considered data from two companies during 4 years, which conducted the public waste collection in 14 municipalities, with a total number of 945 accident cases.
For company A, accidents between 2014 and 2016 were considered. During this period, the number of workers increased from 3380 to 3859. The company was responsible for waste collection in 13 municipalities (9 municipalities in the state of Pernambuco, 2 municipalities in the state of Rio de Janeiro, 1 municipality in the state of Bahia and 1 municipality in the state of Mato Grosso). The total number of accidents which occurred in company A during that period was 756. For company B, were considered accidents that occurred in one year (2017), during which the number of workers corresponded to 2020. The company was operating in one municipality (the metropolitan region of Recife, State of Pernambuco). The total number of accidents which occurred in company B during that period was 189.
This phase of study analysis was subdivided into two parts. First, all accident cases were analysed based on the type of urban cleaning service in which the accident occurred. Subsequently, accidents were grouped by type, and their relative percentage was calculated. The percentages of accidents were afterwards compared between two analyzed companies A and B.

Container as a risk management tool
Company A conducted the public waste collection in 13 municipalities, from which 7 municipalities' implemented containers, while 6 did not. The company decided to implement containers as a strategy to improve safety for workers and increase production. The containers were implemented in 7 from 9 municipalities located in Pernambuco. Company B did not implement any containers during the analyzed period. From the 7 municipalities which implemented containers, six implemented a smaller number of containers, without any quantity control. Therefore, the seventh, with the highest number of implemented containers, was selected to study thoroughly if the implementation of containers would reduce the number of major accidents (sharp materials and falls). The accidents were analyzed during three years, in 2014 when there were no containers, and comparing it with 2015 and 2016 when 776 containers of 1,000 litres were implemented.
The municipality was located in the metropolitan region of Recife, with an area of 2,768 km², with a population of 4,046,845 inhabitants (IBGE -Instituto Brazilian Geography and Statistics 2013). The municipality is coastal with a waterfront of 14 km, and the predominant activities in the sector are services, commerce and industry. Therefore, due to the number of tourists that come to visit the municipality, the generation of waste tends to be higher with the generation of 1,065 kg of waste per inhabitant per day (Recife, 2011). All containers were the same model "Contemar Ambiental", which was illustrated in Figure 2. The containers were localized in the main avenues of the municipality, on state roads and avenues near the beaches. The company localized one container every 50 meters on the beach avenue. In the state roads, the distance between containers was not standardized. Additional containers were localized throughout the city on the main points of waste generation, such as fairs and public squares.
It is important to mention that it is not common to establish containers in Brazilian municipalities, thus having a greater difficulty during the implementation period, since it is necessary first to carry-out environmental education actions with the population for the proper use of containers, as well as to additionally train collection workers. In 2015 all workers received training on how to use containers, while in 2016 training were given only to newly arrived workers. Figure 3 shows the number of accidents by type of service occurred within the analyzed years in companies A and B, and the Pareto principle represented with an orange line. This illustration aims to show the groups of urban cleaning services with most accident cases. The x-axis represents the type of service, the left y-axis the number of accidents that occurred in the service, while the right y-axis shows the percentage of the cumulative of services of the total number of accidents represent the sum of the accidents from the left to the right columns. As shown in Figure 3, there were a total of 945 cases of accidents in analyzed companies A and B. The household collection was responsible for 620 accidents, representing 65.61% of the total number of accidents. Therefore it is clear that it is a priority to solve accidents which are occurring during household collection. The second column named "others" accounted for 79 accidents (8,36%), representing services as tree pruning, selective collecting, maintenance, preservation of public squares, landfill, correlates, special operations and administrative services.  According to Figure 4, accidents with sharp materials represented in company A were 28% (150 cases) and in the company B were 36% (29 cases) of all causes of accidents of each company. Falls were the second major cause of accidents with 25% (133 cases) in company A and 26% (21 cases) in company B. Falls included falls from the truck, falls from standing height and other types of falls. This shows that sharp materials and falls are the two major risks for workers participating in the urban cleaning operation. Company A had various cases classified as "operational failure", which could have included sharp materials, falls, but also any other cause of accident. Therefore, it was decided to leave it as a separate group, rather than speculate with it.

Causes of accidents
The conclusions made by Diniz et al. (2019), analyzing leading causes of accidents in the process of urban waste collection in Brazil, found that in a total of 473 accident cases, 45.03% were caused by sharp materials and 25.37% by falls. Combined, these two causes accounted for 70.40% of all recorded accidents in the urban solid waste collection service. This is in accordance with the results from the present study, where sharp materials and falls were responsible in company A for 53% and company B for 62%, showing that there is a need to focus on reducing those two causes of accidents.

Implementation of the container
The effect of the containers' implementation was studied only in one municipality during the period from 2014 to 2016, as already described in the methodology section. The total number of accidents was 112, where sharp materials and falls caused 66. As those two were the major causes, further analyses were focused on them.  27%. This can be explained with the implementation of containers, as the worker was less exposed to waste, having, therefore, lower risk to suffer accidents caused by sharp materials and or falls during the operation. Figure 6 shows a comparison of the average number of accidents between the municipalities that have implemented containers and those that have not. In the light green group, the cases of the 7 municipalities that implemented containers are represented (except for the year 2014 when containers were still not implemented). In the dark green group are represented the 6 municipalities that have not implemented containers.
As it is illustrated in Figure 6, the municipalities which implemented containers had a decrease in the number of accidents, while in the municipalities which did not implement containers, the number of cases was increasing.
In Table 1 Table 1, the implementation of containers leads to various benefits for waste-collection workers and society. Containers reduce occupational accidents, presence of animals and disease vectors and improve the aesthetic look of the streets.
In the metropolitan region of Recife, it is common to organize "critical points". Such points are use-to accumulate waste in a disorganized way, where bags are torn in the streets, waiting for its collection. With the implementation of containers, such points would be excluded as waste would remain enclosed within them, improving the landscape of the site, reducing the worker's effort and time necessary to collect waste, avoiding bad smell, the proliferation of diseases, among other benefits.  (2015); Contemar Ambiental (2018); Diniz et al. (2018) and SEABRA et al. (2016)).

1
Elimination of unwanted odours, since the containers have lids that seal the bad smell.
2 Reduction and elimination of the incidence and proliferation of disease vectors and animals 3 Reduction in the number of occupational accidents, as the worker is not directly in contact with the waste.

4
It also reduces the number of times that collectors need to get on and off the truck.

7
It avoids the contact of the population and workers with the waste. 8 Waste does not accumulate on sidewalks. Improve the aesthetic appearance of streets and sidewalks by placing bags inside containers, instead of being deposited on the streets.

9
Efficiency of waste segregation at source.
10 Improvement in collection efficiency.
11 Animals do not rip the bags with waste.
12 Protection of the bags from the weather.
13 Decreased clogging of manholes due to the bags that are taken when it rains, consequently reducing the probability of floods.
14 Residents can dispose of the waste 24 hours a day, not needing to wait for the time that the truck passes.
15 Elimination of environmental contamination resulting from improper disposal of waste on public roads.

General discussion
The conclusions made on analyzed data from company A and B converge with conclusions with similar previously conducted studies international and in Brazil, showing that sharp materials and falls represent leading causes of accidents (Oliveira, 2008;Soares, 2014).
One study stated that the falls are influenced by the velocity on which the waste collectors are transported on the backside platform (Jeong; Lee, S; Lee, J., 2016). It is important to notice that the recommendation from ANSI Z245 (2017), specify that during the collection of waste, the workers can transport themselves on it only on distance shorter than 322 meters and velocity lower than 16 km/h. The training of individuals transported on the platform, as well as its dimensions and materials are also regulated.
The following Table 2 shows the percentages of accidents with sharp materials, falls, the sum of the two major causes, other causes and the total number of accidents, representing results from studies which implemented with those which did not implement containers.
In grayscale were marked numbers of accidents in the municipality, which implemented containers, illustrating the decrease after its implementation.
The studies used in Table 2 used a similar methodology to the one used in this study, comparing data gathered from different reports. Still, as each report had different subcategories, there might be some oscillation. It is important to point out that "other causes" increased after the implementation of containers from 12 (2014), to 15 (2015) and 19 (2016). The number of causes within this group was classified as "operational failure", without any clear explanation on what does this group of causes include. This limits the interpretation of data, something which should be resolved in future studies.   The chosen municipality from company A shows that there was a decrease in the number of accidents caused by sharp materials from 2014 to 2015, and having its highest decrease in 2016. In order to fully understand how beneficial was the application of containers; it is important to observe not only percentages but also the number of accidents (represented in Table 2), which is a total amount decreased from 2014 (49 cases) when there were no containers, to 2015 (33) and 2016 (30) when the containers were applied. Figure 8 shows a percentage of accidents caused by falls based on the implementation of containers. Without containers, falls usually caused between 21.87% and 40.82% of accidents. One exception was the study from Velloso, Santos, and Anjos (1997), which classify only 4.47% of cases to be caused by falls. After the implementation of containers, the number of cases caused by falls in the chosen municipality from company A decreased from 32.65% (2014) to 15.50% (2015) and 20% (2016).
Therefore, as illustrated in figure 8, the implementation of containers directly seems to influence the reduction of the number of cases caused by falls. Although in a lower number, sharp materials (8.9%) were also a high risk identified in a study conducted in South Korea, specifying it as one of the principal types of accidents (Jeong; Lee, S; Lee, J., 2016). Falls, on the other hand, were identified by most of the studies as the primary type of accidents. Therefore, these should be the risks to be firstly addressed in future studies and urban waste collecting services. For the implementation of containers, it is essential to plan and analyze the necessary demand of the city. Further on, for that purpose, it is necessary to conduct more thorough analyses of when and how work accidents occurred during the waste-collecting process. Finally, future studies should focus on the reduction of the major accidental causes, where falls represent one of them and investigate if falls usually occurred from the truck or in the standing or running position. Falls from trucks should be additionally screened in order to find out if in those cases, the trucks had all its parts (for example platforms and handholds) were appropriately built (considering the material type and dimensions) and certified for the transportation of workers. Further-on, future studies could investigate if there was a protocol applied when transporting workers if there was a limitation of driving speed while the workers were transported on the platform, if workers had adequate training and if everything was done according to standards for the wastecollection process.

CONCLUSIONS
The urban cleaning service is essential for society. The household waste production is continuously increasing, consequently the investment in the urban cleaning sector. Nevertheless, as there is a need to invest even more in order to reduce the number of occupational accidents.
According to the analyzed data, the household collection was the type of service with the highest number of accidents with 65.61 of the total number of accidents. The sharp materials and falls were the main causes of accidents, accounting for 53% of accidents in the company A and 62% in the company B.
After containers implementation, the data from one municipality show a reduction in the number of accidents caused by sharp materials and falls from 37 without the container in 2014, to 18 with the container in 2015, and 11 with the container in 2016.
The reduction in the number of accidents can be explained with the implementation of the containers. Containers reduced the direct exposure of the worker to the waste, reducing the exposure to sharp materials and reducing the chance of falling or tripping during the operation.
Several suggestions for future studies were given in the discussion part, mainly concerning the leading causes of accidents.