TECNOCIENCIA CHIHUAHUA, Vol. XV (1) e 754 (2021)

https://vocero.uach.mx/index.php/tecnociencia

ISSN-e: 2683-3360

Artículo Científico

Diagnosis of health and safety at work in a Fire

Station located in Chihuahua, Mexico

Diagnóstico de salud y seguridad en el trabajo en una Estación de

Bomberos ubicada en Chihuahua, México

*Correspondencia: Correo Electrónico bbeltran@uach.mx (Blanca G. Beltrán)

DOI: https://doi.org/10.54167/tecnociencia.v15i1.754

Recibido: 15 de enero de 2021; Aceptado: 03 demayo de 2021

Publicado por la Universidad Autónoma de Chihuahua, a través de la Dirección de Investigación y Posgrado.

Abstract

This research presents a diagnosis of safety and health at work based on the Italian Worker´s

Model, for the identification of occupational risk factors of 10 firefighters from Chihuahua, Mexico.

The study variables were: noise, hearing threshold (UA by its acronyms in Spanish), suspended

particles, weight, and body mass index (BMI). The REBA method was employed to detect

ergonomic risks in ascending-descending to the fire unit. Psychosocial demands were evaluated

through DAAS 21 instrument. The level of correlation among hearing threshold (UA), seniority,

age, and BMI were analyzed. The noise exceeded the Maximum Permissible Level (MPL)

established by the Mexican standard. Firefighters with mild to moderate hearing loss were

detected. All the firefighters except one were overweight and obese (BMI = 23 to 30). There was no

correlation between BMI and UA, which indicates the condition of overweight and obese are not

associated with the firefighters’ hearing loss. The concentration of PM2.5 and PM10 particles was

found within the MPL. The ergonomic risk was categorized from medium to very high. The results

of the DASS 21 for each worker showed the presence of moderate stress, moderate anxiety, and

severe anxiety. The research provides scientific evidence that shows occupational risk factors and

helps to take preventive measures.

Key words: Italian Worker´s Model, firefighters, occupational risk factors, working conditions,

safety and health at work.

Sergio González González1, Rosa O. Ramírez Fraire2, Adriana Chávez Calderón2, Eduardo

Santellano Estrada3 y Blanca G. Beltrán2*

1Pondercel S.A. de C.V., Anáhuac Mill/Grupo Copamex, Anáhuac, Chihuahua, México. C.P. 31600.

2Department of Occupational Health, Faculty of Nursing and Nutriology, Autonomous University of

Chihuahua, Chihuahua, Campus UACH II, Chihuahua, México. C.P. 31125.

3Faculty of Zootechnics and Ecology, Autonomous University of Chihuahua, Periférico Francisco. R.

Almada Km 1. Chihuahua, Chihuahua, México. C.P. 33820.

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Resumen

Esta investigación presenta un diagnóstico de seguridad y salud en el trabajo basado en el Modelo

Obrero Italiano, para identificación de factores de riesgo ocupacional en 10 bomberos de

Chihuahua, México. Las variables de estudio fueron: ruido, pérdida auditiva, partículas en

suspensión, peso e índice de masa corporal (IMC). Se empleó el método REBA para evaluar riesgos

ergonómicos. Las demandas psicosociales se valoraron mediante el DAAS 21. Se analizó el nivel de

correlación entre umbral de audición (UA), antigüedad, edad e IMC. El ruido excedió el Máximo

Nivel Permitido (MPL) establecido por norma mexicana. Se detectaron bomberos con hipoacusia

leve a moderada. Todos los bomberos, excepto uno, tenían sobrepeso y obesidad (IMC = 23 a 30).

No existió correlación entre IMC y UA, lo que indicó que la condición de sobrepeso y obesidad no

está asociada a la hipoacusia de los bomberos. La concentración de PM2.5 y PM10 estuvo dentro del

MPL. El riesgo ergonómico se categorizó de medio a muy alto. Los resultados del DASS 21 para

cada trabajador mostraron la presencia de estrés moderado, ansiedad moderada y severa. La

investigación brinda evidencia científica que muestra factores de riesgo ocupacional y coadyuva a

la toma de medidas de prevención.

Palabras clave: Modelo Obrero Italiano, bomberos, factores de riesgo ocupacional, condiciones

de trabajo, seguridad y salud en el trabajo.

1. Introduction

In occupational health, firefighting is classified as a high-risk activity because it takes place in

dangerous environments and conditions. It might cause a permanent disability, injuries in different

parts of the body, hearing loss, burns, and muscle contractions, respiratory damages due to

exposures to leaks of hazardous chemical compounds, combustion, and deadly gases (Guidotti &

Clough, 1992; Díaz et al., 2016; Prell et al., 2020). More than 50% fire-related deaths are due to the

exposure to smoke not due to burns. There are mortal accidents of firefighters caused by the

collapse of architectural elements that sometimes block the possible evacuation routes during a

disaster (Barr et al., 2010; Yang et al., 2014). The firefighter’s brigade, between the general working

population, frequently shows symptoms related to stress, headache, sleep disorders, fatigue, and

irritability (Duran et al., 2018). The working conditions of firefighters are most distinctive among

the working population because of the 24-hour work shifts, the quasi-military work organization,

and the pattern of generally routine firehouse-based activities interspersed with unpredictable calls

for emergency medical care or to fight structural or wildland fires.

In addition to the factors mentioned above, obesity is a firefighter’s risk factor, which has been

linked to increased hearing thresholds. The body mass index (BMI) is a measure of body

composition. Overweight and obesity are associated with an increased risk of hearing loss, and

metabolically unhealthy obesity may confer additional risk (Choi et al., 2011; Hu et al., 2020).

Hearing loss contributes to social isolation, depression, and possibly dementia risk (Croll, 2019).

Firefighters are exposed to other demands such as disaster missions, rescue services, as well as

firefighting in extremely hot and hostile environments (Prell et al., 2020). Due to the firefighter’s

brigade, before the general working population, they frequently show symptoms related to stress,

headache, sleep disorders, fatigue, and irritability (Duran et al., 2018). The Depression, Anxiety, and

Stress Scale (DASS 21), evaluates these negative effects.

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Due to health and safety implications in firefighting, new research needs to be conducted to

examine how firefighters' task characteristics and their work demand influence the development of

work-related musculoskeletal disorders (Kodom-Wiredu, 2019). Currently, research models are

used to contribute to the knowledge base about the ergonomics of firefighting, in particular to find

the multi-variate demands of the job and the attributes and capabilities of operators to cope with

these demands (Gentzlez, 2010). The work-related musculoskeletal disorders imply a wide range of

inflammatory and degenerative conditions affecting muscles, tendons, ligaments, joints, peripheral

nerves, and supporting blood vessels (Kodom-Wiredu, 2019). Regarding ergonomy, the method

Rapid Entire Body Assessment (REBA), allows the analysis of adopted positions by upper body

limbs (arm, forearm, wrist), trunk, neck, and legs.

Firefighters are exposed to a wide range of toxic chemicals due to combustion (volatile organic

compounds, semi-volatile organic compounds, and metals) (Engelsman et al., 2020). On the other

hand, firefighters may be exposed to diesel exhaust, which is classified as a Group 1 carcinogen by

the International Agency for Research on Cancer (IARC) and particulate matter (PM) from vehicles

and off-gas (volatile organic compounds (VOCs), formaldehyde, among others) emitted from idling

vehicles and firefighting equipment, such as clothes, boots, and gloves, from the fire scene (Kim et

al., 2019).

Due to the complexity in the administrative organization and its work processes, it is hard to

evaluate the multiple risks and demands to which firefighters are exposed. There are discrepancies

between the international standard and the health and safety regulations of each country (Ehlers et

al., 2015; Alvarez et al., 2016; Duran et al., 2018; Cohen et al., 2019; Prell et al., 2020).

From this point of view, the objective of this research was to perform a diagnosis of safety and

health at work based on the Italian Worker´s Model, for risk identification and the determination of

physiological and psychological demands in a fire station in Chihuahua, Mexico.

2. Materials and Methods

2.1. Subjects and design

This was an exploratory, cross-sectional study. It involved ten firefighters from a fire station

located in the city of Chihuahua, Mexico. All of them aged between 27-47 years old having a

traditional or rotating work schedule. The study protocol was evaluated by the Institutional Review

Board of the Faculty of Nursing and Nutriology, at the Autonomous University of Chihuahua,

Chihuahua, Mexico, according to the Declaration of Helsinki. The data was recollected in the year

2019.

2.2. Instruments and evaluations

2.2.1 Italian Worker´s Model and the PROESSAT survey

The Italian Worker´s Model, recognizes the collective intelligence of the workers as experts

regarding to working conditions and it operates under three fundamental values: working

experience, consensual validation and the non-delegation (Marín & Pico, 2004). The risks are

studied in three groups: physical (I), chemical and biological (II), and mechanical (V); and the

demands in two groups: physiological (III) and psychological (IV) (Noriega, 1995). They originate

from the different compound elements that make up the process work: in work environments,

objects, activity, organization, and work division (Voguel, 2016). The Italian Worker´s Model has

two basic instruments: I) Collective survey: it collects information, elements, and organization,

through the guide for the study of the labor process and the group questionnaire; II) Risk map: it is

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the visual representation through drawings, schemes, diagrams or any similar form of the results

from the research (Zarate-Amador, 2013).

Its application began with the recognition of the work process and some of the places where the

workforce carried out their activities. The homogeneous group was conformed. A deep interview

based on the questionnaires that make up the instrument within the working hours, was

conducted, using a PowerPoint presentation to visually present the questionnaires. The

participations were audio recorded to ease the analysis of the information. The procedure included

eight sessions of three hours each within the working day and with informed consent, being the

recordings eliminated after their capture.

An epidemiological type survey such as the “Workers’ Health Evaluation and Monitoring

Program” in Mexico (PROESSAT by its acronyms in Spanish), was used to capture the

demographic, social, risks, demands, and health issues (Balderas-López, 2019). The PROESSAT

survey identifies the presence of symptoms that allow make up presumptive diagnoses of various

health damages, including mental, psychic, psychosomatic disorders, and musculoskeletal. The

printed form of the PROESSAT survey was given to the firefighters who voluntarily participated in

its filling.

2.2.2 DASS 21 instrument

The DASS 21 instrument has the advantage of being a self-report instrument; short, easy to answer

with valuable psychometric properties (alpha values from 0.87 to 0.88 for depression, between 0.72

and 0.79 for anxiety and from 0.82 to 0.83 to stress) in several studies (Elbay et al., 2020; Jian et al.,

2020). It was done in writing, each item is answered according to the presence and intensity of each

symptom, on a Likert-type response scale of 0 to 3 points. Each scale has seven items and its total

score varies between 0 and 21 points to know the levels of stress, anxiety, and depression (Elbay et

al., 2020).

2.2.3 Noise Measurements

The noise coming from the Ford Model 1982 extinguishing class was evaluated, in its different

sirens; truck in moto-pump phase (in areas of the control panel and water intakes); fan noise and

hydraulic tool motor. A total of 180 measurements were executed by generating source. The

integrating sound level meter was used (SoundPro ™ Datalogging, 3 M brand, US) following the

recommendations of the Mexican regulation (NOM-011-STPS-2001).

2.2.4 Audiometry study and BMI calculations

It was carried out based on the method of American Medical Association (AMA), to know the

auditory sensitivity of the firefighters. The auditory canal was examined with a stethoscope, to

verify that the ducts were free and there was not any inflammation or pathology. The participant

had to stay 15 minutes previous to the trial, outside of a noisy environment and without making

major physical efforts. It was played only the audiometry tone in a cabin with an INVENTIS

instrument (model Bell basic/plus AU1D-31, US). The data was processed by a DAISY Inventis

Software computer. The firefighter responded to the auditory impulses he perceived by pressing a

button. The frequencies evaluated were 250, 500, 1000, 2000, 4000, 6000, 8000 Hz. Then, it was

proceeded to weigh and measure the participant’s height, to calculate their body mass index (BMI).

2.2.5 Measurements of gases and suspended particles

It was performed in three different areas: machines room, out-of-room station, and the living room.

In the mobile unit 871, three measurements of 15 minutes were executed, placing the environmental

monitor at 1.5 meters from the exhaust of the mobile unit, simulating the distance and height at

which the personnel are at the time of work. The instrument used was a 3M ™ EVM-7 air and

particle quality monitor, US. The density of the evaluated particles was 2.5 and 10 μg·m-3 and the

toxic gases selected for the environmental measurements were: dioxide and monoxide carbon (CO2

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and CO), acetaldehyde, propaldehyde and volatile organic compounds (VOC), such as:

chlorobenzene, formaldehyde, toluene, and benzene. Based on what is stablished in the Mexican

regulations NOM-010-STPS-2014 and NOM-025-SSA1-2014 (NOM-025-SSA1-2014 & NOM-010-

STPS-2014), the data analysis was carried out.

2.2.6 Ergonomics analysis

The REBA applications are related to preventing injury risks, which are associated with the posture,

mainly of the musculoskeletal type, indicating corrective actions. It is the result of cooperative work

carried out by teams of ergonomists, physiotherapists, and nurses after identifying/analyzing

around 600 working postures (Hita-Gutiérrez et al., 2020).

Two work activities were considered: approaching the unit and rolling hoses, which are carried out

regularly for the workday and marked as potentially harmful by the worker, due to uncomfortable

positions adopted and repetitiveness. It was observed the ascent-descent of the personnel to the

unit and techniques of rolling hose in the ground, during 72 hours to be registered and evaluated in

photos and video. The information was processed in an Excel spreadsheet, the degrees of

inclination of joints, extra loads, and sudden movements were evaluated to quantify the level of

risk in the adopted positions. The risk factors evaluated are: static muscular works, important

postural changes, repetitive movements, obtaining punctuation, level of action, risk and required

action.

2.3. Statistical analysis

Data were presented characterized in their central tendency and dispersion through the mean

±SD (standard deviation), respectively. Additionally, and assuming the data distribution was

normal the Pearson correlation between pairs of variables was obtained. The most frequently used

α values are: 0.01, 0.05, and 0.10 (Wayne, 2005). The p-value or significance level of 0.1 was

stipulated at the authors' discretion. The SAS 9.1 (SAS, 2006) software was used in the analysis.

3. Results and Discussion

3.1. Diagnosis of safety and health at work

In México, there is not much information available in this regard, partly because firefighters only

have initial medical assistance (medical consultation) within the services allowed by the Mexican

Institute of Social Security (IMSS by its acronyms in Spanish), but workplace risks and accidents are

addressed by the State Health Department, as this institution is not obliged to generate statistics for

occupational diseases, it is difficult to have concrete figures (Meléndez-López et al., 2018).

Other relevant problems are the lack of financial resources for the payment of salaries similar to

purchase and equipment, and more training. All of the above affects fire departments with very few

personnel, since, in certainty, this public service becomes an altruistic endeavor rather than a job

(Bárcenas-Castro & Aguilera, 2012). The subjective identification of the risks and demands through

the Italian Worker´s Model questionnaires, are presented in Figure 1. The application of the

PROESSAT survey allowed describing the generalities of the study population and allows the

calculation of a risk percentage. The age range was around 27-44 years old, with an average of 37

years. The working seniority varies around 4-23 years, 50% of the firefighters present a high

domestic load index and 100% is identified and proud of their work. Both methodologies were in

agreement with the individual characterization of the physical risks (sudden changes in

temperature, poor lighting, and humidity), chemical risks (dusts, fumes, and gases or vapors), and

physiological demands (awkward positions and musculoskeletal disorders) and psychosocial

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demands (high concentration, meticulous tasks, night work, strict supervision, rescue of people in

danger). Regarding worker´s health it was identified damages to the musculoskeletal and

respiratory system and other symptoms such as physical fatigue, depression and anxiety, sleep

disorder, migraine, and low back pain were identified. Most of the activities of the firefighters are

carried out outside the facilities, which makes it difficult to graphically represent the risks and

demands in a static and geographically located plane. Therefore, it was not possible to design a risk

map.

Figure 1. Subjective identification of risks and demands through the Italian Worker´s Model and PROESSAT

survey.

Figura 1. Identificación subjetiva de riesgos y demandas mediante el Modelo Obrero Italiano y la encuesta

PROESSAT.

This research performed a diagnosis of safety and health at work based on the Italian Worker´s

Model and PROESSAT survey for the identification of risks at a fire station in Chihuahua, Mexico.

The main risks and demands found are related to other studies, where five large risk areas for

firefighters are mentioned: exposure to hazardous substances, ergonomic factors and of physical

load, exposure to noise, psychosocial aspect and exposure to biological and chemical risks (Duran et

al., 2018; Prell et al., 2020).

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3.2. The DAAS 21 results

The DASS21 measurements were realized as follows: The instrument has 21 items, with four

response alternatives in Likert format, which range from 0 ("It does not describe anything that

happened to me or I felt during the week") to 3 ("Yes, this happened to me a lot, or almost always ").

To answer, the slogan establishes to indicate to what extent the sentence describes what happened

or felt the person during the last week. This instrument has the advantage of being a self-reporting

scale, short, easy to administer and answer, and its interpretation is simple. The obtained results for

stress (6.9-10.4), anxiety (5.3-5.4) and depression (2.5-2.8), are within the normal range for the three

scales (0-14, 0-7, 0-9 for stress, anxiety, and depression, respectively) in a general analysis. However,

six of the participants presented moderate stress, three mild anxieties and another one severe

anxiety. These results were similar to those obtained with the PROESSAT in its section Assessment

of Risk and Demands. The psychosocial risk assessment was carried out by a student with a

master's degree in Occupational Health and he is not a specialist in the administration of

psychological tests, which requires making recommendations that are not of such a specialized

interpretation. The results must be expressed simply and clearly to the company management since

psychosocial risks related to working concern aspects of work management, social and

organizational contexts, with the ability to generate psychological or physical damage. Psychosocial

risks cannot, analysed as environmental measurements rather than individual measurements

(psychological attributes). The individual results for each worker’s DASS 21 scale show the fact that

six firefighters had moderate stress, three firefighters had moderate anxiety and one firefighter had

severe anxiety, that is to say, these three pathologies are present even though the DASS-21 general

analysis scale does not detect them. Besides, health damage analysis (PROESSAT survey) also

showed physical fatigue, depression, stress, anxiety, sleep disorder, and migraine. From these

points of view, it was possible to determine that psychosocial risks were present in the firefighters'

sample. This fact was important due to these pathologies: stress, anxiety, and depression. Their

consequences are the core point of interest for understanding psychosocial risk factors because their

repercussions on both health and productivity (Vilchis-Rea & López-Hernández, 2017; Balderas-

López et al., 2019; Uribe et al., 2020).

3.3. Noise

The results of the measurements made to unit 875 with a normal operation management, where

the sound levels and the different sirens of the engine were evaluated, are shown in Table 1. The

exposure time will depend on the distance of the service and the number of the emergencies

required during the day. The exposure to the noise is considerable inside and outside the cabin. The

noise results for the unit 871 with the revolutionized engine and the water pressure pump activated

was 83.7 ± 0.2 dB (A), evaluated at the floor level in water intake area. In the control panel it was

81 ± 0.8 dB (A), areas where the machinist operator does his work. The evaluation of the noise

generated by the fan, used in the cooling or extraction of air, is performed both, indoors and

outdoors, the results were 95.3 ± 2.3 dB (A) and 93.2 ± 2.8 dB (A), respectively. The hydraulic tool

motor for extraction generates 81.3 ± 0.7 dB (A).

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Table 1. Noise measurements performed to the unit 871.

Tabla 1. Mediciones de ruido realizadas en la unidad 871.

Note: Results were expressed as the average of 180 replicas ± Standard Deviation.

The results of noise measurements are consistent with what has been reported in other researches

where it is indicated firefighters are frequently exposed to high levels of noise from various sources:

vehicle sirens, horns, machine and tool motors. Levels of more than 100 dB (A) can be reached in

the response to emergencies (Alvarez et al., 2016; Cohen et al., 2019). In this research, the noise

values exceeded the maximum limits allowed by the Mexican standard (NOM-011-STPS-2001).

Exposure to noise at work can be harmful to health from the workers. The best-known effect of

noise at work is hearing loss. However, it can also increase stress and multiply the risk of an

accident.

3.4. Audiometry

Choi et al., (2011) presented a theoretical framework describing the relationship between

working conditions, health behaviors, and obesity in firefighters. However, the associations

between working conditions of firefighters and obesity, and the relationships between working

conditions and health behaviours for obesity in firefighters remain to be clarified.

There are diverse factors such as overweight, obesity, age, and time of exposure to noise appears,

that influence the hearing loss. Table 2 shows the results of the audiometry (applied to nine

firefighters) their age, BMI, labor seniority, the hearing threshold obtained and their categorization

according to the World Health Organization (WHO). The results of the measurements showed that

there is hearing loss among the studied firefighters and a low hearing of the personnel in the

frequencies of 4000  6000 Hz. This phenomenon shows that the ear has a higher difficulty for a post

occupational recovery. On the other hand, the level of linear association between the measured

variables was analyzed, considering a significant correlation at a level of 0.1, since, the sample of

firefighters is small. Table 3 shows coefficients correlation between the hearing threshold (UA),

seniority, age and BMI.

Table 2. Results of the audiometry study.

Tabla 2. Resultados del estudio de audiometría.

Firefighter

Age

(years)

BMI*

Seniority

(years)

UA*

dB (A)

Hearing loss levels

WHO

22.3

mild

32.1

severe

30.4

normal

26.8

normal

27.4

mild

Measurement

area

Running engine

dB(A)

Sirens Wail

dB(A)

Sirens Yelp

dB(A)

Inside the cabin

73.8 ± 4.9

94.3 ±1.6

Outside seats

75 ± 4

94.7 ±1.4

94.5 ±1.1

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29.1

mild

42.8

normal

29.7

normal

31.8

moderate

*BMI= body mass index; UA= hearing threshold.

There was a strong direct linear association (r = 0.65, p= 0.0574), between the labor seniority of

firefighters and UA. It means, being firefighters as their years of service increases their auditory

level decreases in a high proportion, being that their UA are increasing. Likewise, a positive

correlation between the variables “Age” and “Seniority” was found (r = 0.72, p= 0.074). As

firefighter’s age increases, so will their seniority. Moreover, there is not enough statistical evidence,

but it does exist a trend between the correlation of the variables “Age” and “UA” (r = 0.53, p= 0.14).

Which suggests that for this study and under the conditions, in which the same is carried out, age

can be or not, a risk factor for suffering hearing loss. A similar behaviour (r = 0.54, p= 0.13) occurs

between the variables “BMI” and “seniority,” that is to say, the younger firefighters with a less

seniority present a higher BMI.

Table 3. Correlation Analysis.

Tabla 3. Análisis de correlación.

Ratio of Variables

Significance Level

(p)

Correlation Coefficient

( r )

Linear

Association

Seniority  *UA

0.058

0.65

yes

Age  UA

0.14

0.53

Tendency

BMI  UA

0.76

-0.11

Age  Seniority

0.074

0.62

yes

BMI  Seniority

0.13

-0.54

Tendency

Age  BMI

0.0085

-0.80

yes

*BMI= body mass index; UA= hearing threshold.

Finally, it did not exist a linear correlation between the “BMI” and the “UA” (r = 0.11, p= 0.76).

Which indicates that the condition of overweight and obesity (BMI) is not associated with the

firefighters’ hearing loss.

The firefighters show hearing loss and low hearing at frequencies of 4000 and 6000 Hz. Researchers

agree on the fact there is a greater hearing loss after the sixth year of exposure and a loss in hearing

acuity at the highest frequencies between 3000 Hz and 6000 Hz, in particular, around 4000 Hz

(Bufano, 2013), that is, as firefighters increases their years of service, their hearing level decreases.

In this study and under the conditions in which it takes place, age can be or not a factor of risk for

suffering hearing loss (there was a trend between age and UA variables). Despite this, the natural

aging of the ear by age must be taken into account, which will affect each individual in a different

way (Hong et al., 2013), because, the hearing loss related to aging is a biological phenomenon of the

ear which no one can escape, beginning around 20 to 30 years of age and it appears symptoms at 50

to 60 years of age. Therefore, it could be considered as a natural condition that increases its

prevalence with age (Díaz et al., 2016).

The BMI was calculated and used as an indicator for obese and overweight, conditions can affect

the metabolism of glucose in the body causing internal ear dysfunction with damage to hearing and

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balance (Fernández et al., 2011). Due to obesity has a significant effect on vascular function, and this

may have an impact on highly vascular organs such as the auditory system (Dhanda and Taheri,

2017). According to the results, all the firefighters in the study, except one, were overweight

(BMI=23) and obese (BMI=30). However, the correlation analysis showed for this study, the variable

of BMI and auditory threshold, does not correlate, which indicates the condition of overweight and

obesity are not associated with the firefighters’ hearing loss. However, in order to prevent the

obesity risk factor a nutritional intervention program for firefighters was recommended. These

programs often include personal diet, hereditary factors, psychological evaluations, and physical

activation (Choi et al., 2011). Nutritional Intervention Program is considered to improve the

variables of BMI and weight. Reduction of overweight and obese in firefighters is promoted.

Besides, these two conditions are strongly associated with other non-communicable diseases such

as diabetes and high blood pressure.

3.5. Measurements of gases and suspended particles

At the scene of a fire, firefighters are frequently exposed to CO, CO2 and VOC, among others

(Guidotti & Clough, 1992). The values found for benzene, VOC, propaldehyde, acetaldehyde, were

3.7, 4.2, 7.7, 24.2 ppm, respectively (Table 4 and Figure 2). The concentration of benzene (3.7 ppm)

exceeds the MPL established by NOM-010-STPS-2014 (2.5 ppm). Acetaldehyde was found near the

MPL (25 ppm). The same regulation establishes an MPL of 30,000 ppm for CO2. The values found

(912.5 ppm), are within the MPL (working day of eight hours a day and a working week of forty

hours). The CO was found at a concentration of 19.44 ppm, a value below the 200 ppm for CO,

established by the Institute of Occupational Health and Safety (NIOSH) (Ehlers et al., 2015).

Table 4. Comparison between VOCs obtained values and MPL’s by the NOM-010-STPS-2014.

Tabla 4. Comparación entre los valores obtenidos y los MPL permitidos por la NOM-010-STPS-2014

VOCs

aObtained values (ppm)

MPL’s by NOM-010 (ppm)

VOCs (total)

4.2 ± 0.3

Benzene

37 ± 0.5

Propaldehyde

7.7 ± 0.1

Acetaldehyde

24.2 ± 0.5

a*Results were expressed as the average of 3 replicas ± Standard Deviation.

*Value not found.

In this research, measurement of gases and particles were carried out in the transport unit, where it

was found benzene concentrations were higher than the MPL by the regulation consulted. These

compounds represent a chemical risk, especially due to combustion fumes and the difficulty of

analyzing them, since their concentration varies depending on the stage of the fire, and their

emission continues even after the fire extinguishes (Vilchis-Rea, 2017). This implies the firefighters'

exposure to these chemical substances, which cause effects such as deterioration and affectation of

the lung tissue some pass into the bloodstream and other parts of the body, preventing the red

blood cells from carrying oxygen. Besides, breathing them can cause loss of consciousness,

suffocation, poisoning, even death. The symptoms will depend on the dose and the time of

exposure.

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Figure 2. Comparison between VOCs obtained values and MPL’s by the NOM-010-STPS-2014.

Source: Table 4.

Figura 2. Comparación entre los valores obtenidos y los MPL permitidos por la NOM-010-STPS-2014.

Fuente: Tabla 4.

The measurements obtained for PM10 and PM2.5, were of a density of 4.13 μg·m-3 and 1.88 μg·m-3,

respectively. Values that were within the corresponding normativity (NOM-025-SSA1-2014). PM2.5

and PM10 particles are associated with health problems (respiratory and cancer) (Prell et al., 2020),

however, in this investigation, the concentration of these particles was within the MPL by NOM-

025-SSA1-2014, the USEPA (35 μg·m-3 and 150 μg·m-3 for PM10 and PM2.5, respectively) and WHO

regulation (50 μg·m-3 and 25 μg·m-3 for PM10 and PM2.5, respectively) (Kim et al., 2018).

3.6. Ergonomic analysis

The analysis carried out through REBA method showed a very high risk in the ascending and

descending activity to the fire unit, as it does not have any stirrup. The punctuation calculated for

this activity was 13, with a “very high” level of risk, which suggest immediate action. On the other

hand, hose winding activity had a punctuation of 7, with a “medium” level of risk, indicating that it

is necessary to implement the action. Due to this, it is possible that some back injuries, muscular

strains and injuries caused by falls are shown.

The results of the ergonomic measurements through the REBA, showed a categorization of risk

between “very high” and “medium” in the analyzed postures. The risk was high enough for these

tasks to warrant modification and changes. The suggested recommendations given included

creating new mechanical and technical devices, modifying existing devices, and making workers

aware of associated risks to reduce the threat of injury (Hita-Gutiérrez et al., 2020). Then carry out a

re-evaluation using the REBA to obtain elements would make the authorities aware of the

investment in infrastructure and equipment of fire stations.

VOCs (total) Benzene Propaldehyde Acetaldehyde

VOCs concentration (ppm)

Obtained values (ppm) Standard values (ppm)

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4. Conclusions

Occupational health in firefighters is a subject studied insufficiently at an international level. In

this research work was possible to realize a diagnosis of safety and health at work based on the

Italian Worker´s Model, for risk identification and the determination of physiological, and

psychological demands in a fire station in Chihuahua, Mexico. The methodology employed

included the Italian Worker´s Model and PROESSAT survey, both are widely used to diagnose

occupational health in our country. Exposure to noise is unavoidable, difficult to assess and

prevent, so the following measures are necessary to adopt such as: the elimination of risk,

acquisition of more closed cabin transport units with air conditioning system so that personnel can

be transported with closed windows, pneumatic and modern hydraulic tool, engineering measures,

implement established predictive and preventive maintenance programs, the application of a

hearing conservation program, audiometry studies on a regular basis (at least once a year), personal

protective equipment. Future biomonitoring studies recognizing and assessing the range of

firefighter’s chemical exposure would be beneficial. This study provided some data to understand

the relationship between obesity and hearing loss in the firefighters’ sample. The individual results

for each worker’s DASS 21 scale show the fact that six firefighters had moderate stress, three

firefighters had moderate anxiety and one firefighter had severe anxiety, that is to say, these three

pathologies are present even though the DASS-21 general analysis scale does not detect them. The

correlation analysis showed for this study that the variable of BMI and auditory threshold were not

correlated, which indicates the condition of overweight and obese is not associated with the

firefighters’ hearing loss. The results of the ergonomic measurements through the REBA, showed a

categorization of risk between “very high” and “medium” in the analysed postures. The risk was

high enough for these tasks to warrant modification and changes. Firefighters knew the risk

factors. However, they not knew the magnitude of negative health effects. The main contribution of

this research was the evaluation of risk factors and the dissemination of its results in the firefighting

community. Changes in the transport unit and personal protective equipment, a calisthenics

program to improve firefighters' physical strength, agility, coordination, and flexibility, were made.

Acknowledgements

Sergio Gonzalez thanks to the Council of Science and Technology (CONACYT) and to the

Autonomous University of Chihuahua (UACH), for the grant awarded to obtain a Master’s Degree

in Health in the Workplace. The authors would like to thank Firefighters department and Civil

Protection of the city of Chihuahua, México for offering raw dates to fill the IWM´s questionnaires

and PROESSAT survey.

Conflicts of interest

All authors have no conflicts of interest to declare.

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TECNOCIENCIA CHIHUAHUA, Vol. XV (1) e 754 (2021)

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