Transactional Theory of Stress (TTS), proposed by Lazarus and Folkman (13), is a widely recognized framework for understanding how individuals perceive and respond to stress. The model posits that stress does not arise directly from external stimuli, but rather from an individual's cognitive appraisal of those stimuli and their perceived ability to cope (10). According to this theory, when an individual encounters a potential stressor, they first engage in primary appraisal, evaluating whether the event poses a threat, harm, or challenge.

In addition to primary appraisal, TTS highlights the concept of secondary appraisal, which refers to an individual's evaluation of available resources and capacity to cope with a stressor (13). While primary appraisal determines whether a stressor is perceived as threatening, challenging, or harmful, secondary appraisal influences the selection of coping strategies. In the context of this study, secondary appraisal is implicitly reflected in the adoption of problem-focused and emotion-focused coping strategies by special equipment operators. That is, operators evaluate their capacity and resources to manage stressors such as low social status, harsh working environments, physiological fatigue, and responsibility pressure, and this evaluation guides their choice of coping responses.

The primary appraisal refers to an individual's assessment of whether the event is a threat, harm or challenge (10). Threat appraisal (TA) occurs when the situation is perceived as potentially harmful, posing risks to wellbeing or performance, leading to stress or anxiety, the scale usually covers perceived severity (14). An operator might fear the possibility of accidents or mistakes when using or repair the hazardous equipment (e.g., ropeway). Harm appraisal involves the recognition that damage has already occurred, whether physical, emotional, or in terms of performance (13). Challenge appraisal (CA) arises when individuals view a situation as an opportunity for growth or achievement, motivating them to engage positively (15). For example, an operator might see handling complex equipment as a chance to develop technical skills.

In response to appraisal outcomes, individuals may adopt various coping strategies, resulting in differential performance outcomes. Problem-focused and emotion-focused coping strategies are typical coping types (12). Problem-focused coping involves the belief that the stressor is controllable and that, through concerted effort, individuals can alter an environment that is perceived as challenging. Emotion-focused coping refers to the process of alleviating negative emotions through cognitive strategies such as avoidance, distancing, or identifying positive value in negative events, allowing individuals to reframe their interpretation of the stressor without altering the objective situation (13).

Outcome is result of the interaction between the individual, the stressor, and the coping mechanisms (11). In this study, outcome is regarded as safety behavior, which is the result after the process of operators coping the appraisal from stressor.

In recent years, TTS has been widely applied in analyzing the behavior of high-risk occupational groups (16). The theory seeks to explain how stressors are linked to an individual physiological, psychological, and behavioral responses, and how these responses, in turn, are related to their overall behavior. This aligns with the purpose of the present study, which aims to identify the mechanisms through which stressors associated with the safety behavior of special equipment operators. Drawing on prior research, this study posits that stressors experienced by special equipment operators, to explore how the stressors (low social status, harsh work environment, physiological fatigue and responsibility pressure) are related to their safety behavior through two key mechanisms of appraisal (including threat appraisal and challenge appraisal and harm appraisal) and coping (including emotion-focused and problem-focused coping strategies). Figure 2 presents the conceptual framework of this study.

Despite the vital role of special equipment and its operators across various sectors, such as the chemical, oil and gas, power, and entertainment industries, these workers often face low social status and limited societal recognition. In China, the educational attainment of special equipment operators is generally low, with many relying primarily on manual labor to earn a living (17). Compared to white-collar professionals, they tend to occupy a lower social position. This lack of recognition can result in feelings of isolation and frustration, which have been identified as occupational stressors (18, 19).

From a cognitive appraisal perspective, however, low social status represents a relatively stable and enduring condition rather than an acute or episodic demand. According to the transactional theory of stress, stressors that are persistent and normalized may not consistently elicit strong threat appraisals, as individuals gradually adapt to their circumstances and recalibrate expectations. In this sense, low social status may not be immediately or uniformly appraised as threatening, particularly when individuals perceive limited alternatives or accept their social position as relatively fixed. Over time, however, the persistent absence of validation and societal acknowledgment can erode emotional wellbeing, contributing to chronic strain rather than acute threat responses (20).

Nevertheless, prior research suggests that low social status can elicit threat appraisals under certain conditions, particularly when it heightens perceptions of uncertainty, uncontrollability, or potential loss. In the context of special equipment operators in China, low entry requirements and high replaceability may increase concerns about job security and future prospects. Supporting this view, Scheepers and Ellemers (21) demonstrated that individuals assigned to low-status positions exhibited physiological threat responses when evaluating their subordinate standing during motivated performance tasks. However, such threat responses are likely contingent on situational cues and individual differences, rather than being a uniform consequence of low social status.

While challenge appraisals are generally linked to positive outcomes such as increased engagement and better performance (22), in the context of China's large population and rapidly aging workforce, improving the social status of special equipment operators is particularly difficult. Given the structural constraints and limited upward mobility, these workers may find it challenging to reframe stressors as opportunities for personal growth or achievement. Consequently, status inequality may inhibit proactive, growth-oriented interpretations of job demands, thereby reducing the likelihood of forming challenge appraisals. Based on above discussion, we formulate the following hypotheses:

The harsh working environment refers to those outer environmental conditions (e.g., the very warm and extremely cold climates) that are difficult for people to work in (23). It has been widely recognized as a key factor influencing workers' safe and unsafe behaviors (24). The special equipment sector is characterized by a high incidence of occupational accidents and challenging working conditions, such as poor lighting, extreme temperatures, and exposure to hazardous materials, which pose substantial difficulties for operators (25). For example, pressure vessel operators frequently work in extreme environmental conditions, such as high-temperature settings (e.g., boiler rooms) or low-temperature zones (e.g., areas surrounding liquefied gas storage tanks). In some cases, they are required to perform inspections or maintenance tasks within confined spaces, such as the interior of storage tanks. Current study proved that number of accidents in the workplace increase due to the workers' negative emotion (e.g., irritation, anger) that are triggered by the uncomfortable environment (26). Also, the working environment has been consistently identified as a major contributor to task-related stressors across diverse occupational contexts (27, 28). Thus, harsh working environment was considered as one of the stressors in this study.

Besides, from the perspective of the TTS (13), such harsh environments can be subjectively appraised by operators in different ways. Specifically, they may be perceived as threat stressors, due to concerns about potential future health issues, such as the extreme cold environment can decrease job performance, also occurs when the core body temperature falls significantly (26). Harm stressors, as a result of psychological trauma stemming from past accidents or injuries, like the fall accident caused by workers repairing amusement facilities at high altitude. Also, challenge stressors, when individuals interpret the environment as an opportunity to improve their skills and resilience. This view is consistent with findings by Liang (29), who suggest that under certain complex conditions, employees may exhibit greater creativity and proactive behavior when confronting stress. Based on above discussion, we formulate the following hypotheses:

Physiological fatigue is a prevalent condition among special equipment operators due to long working hours, repetitive tasks, and physically demanding activities, which can compromise safe and efficient performance (30). Operators frequently work in extreme or variable outdoor conditions, such as intense heat, cold, heavy rain, snow, or strong winds, further exacerbating fatigue. For instance, forklift operators often work up to 12 h per day, while boiler workers may need to install or repair equipment outdoors under harsh climatic conditions. Despite its traditional conceptualization as an outcome of stress, physiological fatigue can also function as a stressor in high-risk occupational contexts. According to the Transactional Theory of Stress (TTS) (13), stress arises from the interaction between environmental demands and individual coping resources. Within this framework, fatigue represents a salient situational strain that can impair cognitive appraisal and diminish coping efficacy. This conceptualization aligns with the Job Demands–Resources model, which posits that sustained job demands can lead to fatigue, which in turn shapes appraisal and behavior (20, 31, 32). Occupational health authorities also recognize fatigue as a critical factor influencing performance and safety outcomes (33). Thus, this study identifies physiological fatigue as a key stressor and seeks to investigate its association with the safety behavior of special equipment operators.

Besides, when fatigue becomes overwhelming, it tends to elicit operators' threat and harm appraisals. Operator may feel the extreme physiological fatigue will cause occupational diseases, such as cervical spondylosis, cardiovascular disease. Also, Xing et al. (34) indicated that the physiological fatigue can induce the mental fatigue status and other mental performances of the brain. It means that the harm (mental fatigue) from physiological fatigue already occurred. Similarly, for special equipment operators, it also can be explained that physiological fatigue may arise their harm appraisal. Moreover, fatigue exacerbates stress when operators are expected to maintain high performance despite diminishing energy and concentration levels (35). In such conditions, challenge appraisals, which involve perceiving a situation as an opportunity for growth or mastery, may also be adversely affected, as physical fatigue inhibits the generation of proactive, goal-oriented thoughts and behaviors. This view is supported by Zhang et al. (17), that construction workers' physical fatigue is negatively associated with their cognitive ability and motion ability. Based on above discussion, we formulate the following hypotheses:

Job responsibility refers to the extent to which workers are held accountable for the outcomes of their work (36). Integrating this concept with the definition of stress, this study defines responsibility pressure as the psychological burden arising from being accountable for the safe operation of complex machinery and the wellbeing of others in the workplace. Special equipment operators often face serious consequences for errors, which may result in accidents or injuries. In China, the insurance mechanism for special equipment accidents remains underdeveloped. Consequently, when such accidents occur, operators may be required to assume part of the resulting liability. For instance, through revocation of their professional qualifications or financial penalties. Therefore, given the complexity of their work environment and the high stakes involved, operators frequently experience considerable stress. Besides, Responsibility has also been identified as a major contributor to task-related stressors across a wide range of occupations (19, 28). Accordingly, this study includes responsibility pressure as a key potential stressor.

For special equipment operators, when responsibility pressure is perceived as overwhelming or likely to result in failure and negative consequences, it may be appraised as a threat. For instance, forklift operators are susceptible to delivering incorrect goods or unintentionally causing harm to others due to operational errors. Motivated by a strong sense of responsibility to ensure smooth workflows and protect the safety of those around them, they often experience considerable stress. However, since such errors are frequently unpredictable and difficult to fully control, operators may interpret them as potential threats. This view is supported by Baethge et al. (37), who noted that when perceived responsibility exceeds an individual's coping capacity, it can become a threat stressor, thereby intensifying stress levels.

Conversely, responsibility pressure may also represent an opportunity for personal growth, learning, or achievement. Out of fear of being held accountable, operators may proactively improve their skills or heighten their concentration in order to prevent accidents. In this regard, responsibility pressure may be appraised as a challenge. This interpretation is consistent with Van de Poel and Sand (38), who emphasized that accountability and responsibility are central to fostering responsible innovation. Therefore, based on above discussion, we formulate the following hypotheses:

Although the relationship among threat appraisal, emotion-focused coping, and safety behavior has been examined in other domains, such as information security (39) and construction work (40), the findings remain inconclusive. For instance, Liang et al. (41) demonstrated that emotion-focused coping mediates the relationship between threat appraisal and safety behavior in the context of IT. In contrast, Krok et al. (42) found that this mediating role of emotion-focused coping was not observed in the associations between threat appraisal and survivors' health behavior among survivors during the COVID-19 pandemic. These inconsistencies underscore the importance of investigating these relationships in new, context-specific settings, such as special equipment operation, which is an area that remains underexplored.

Besides, in high-risk and high-stress occupations like special equipment operation, understanding how individuals appraise threats and respond emotionally is critical for promoting safe work practices. Prior studies have shown that threat appraisal is significantly related to the adoption of emotion-focused coping strategies in high-stress environments (43), and emotional regulation can contribute to safety behaviors (44). That is, threat appraisal may be associated with safety behaviors through emotion-focused coping strategies. Guided by the TTS proposed by Lazarus and Folkman (13), this study seeks to clarify the psychological mechanisms linking threat appraisals to safety behavior. Specifically, it explores whether emotion-focused coping serves as a mediator in this relationship. Thus, we formulate the following hypothesis:

When operators encounter hazardous environments or recall past accidents, they may interpret these experiences as indicators of irreversible harm, triggering emotional distress such as anxiety, fear, or helplessness (45, 46). In response to such harm appraisals, individuals are more likely to adopt emotion-focused coping strategies, which aim to regulate internal emotional states. These strategies may include avoidance, denial, self-blame, or emotional venting (47). Although emotion-focused coping can offer temporary psychological relief, prior research suggests that in high-risk operational contexts, such strategies are often ineffective, as they do not address the root causes of the stressor or promote safety compliance (48–50). Accordingly, emotion-focused coping may appear to have limited association with on the relationship between harm appraisal and safety behavior.

However, based on the Transactional Theory of Stress (TTS), it is also plausible that emotion-focused coping serves as a mediator in this relationship. Specifically, when harm is appraised, operators may engage in emotionally driven coping behaviors, such as talking with friends or participating in leisure activities, to reduce negative emotional responses and reframe their perception of harm. This form of emotion regulation may help restore a sense of control and is associated with an increased capacity to engage in safe behaviors. Therefore, harm appraisal may be indirectly associated with safety behavior through the mediating role of emotion-focused coping. As mentioned above, we formulate the following hypothesis:

Lee et al. (51) found that problem-focused coping strategies significantly improved safety compliance in the manufacturing industry, resulting in a 15% reduction in workplace accidents. These findings suggest that problem-focused coping plays a crucial role in enhancing workplace safety. Given that the special equipment industry is classified as a high-risk sector, it is particularly important to identify the role of problem-focused coping in improving safety behavior.

Current research has discussed the mediator role of problem-focused coping in the relationship between Challenge appraisal and safety sector in different aspects. For example, Kim et al. (52) stated that workers in high-risk industries, who appraised stressful situations as challenges, were more likely to adopt problem-solving strategies. This appraisal process enhances coping efficacy, leading to improved safety behavior and reduced risk of accidents. Similarly, Gonzalez and Morris (53) provides evidence that challenge appraisal is a key predictor of problem-focused coping in high-stress occupations. Their research demonstrates that employees who perceive workplace stressors as challenges are more likely to adopt proactive coping strategies, which in turn enhances their adherence to safety measures. These findings support the notion that problem-focused coping serves as a mediating mechanism between challenge appraisal and safety behavior, thereby promoting safer work practices. However, there is a limitation of empirical research identity the mediator of problem-focused coping in the relationship between Challenge appraisal and safety behavior in special equipment industry. Thus, the following hypothesis is proposed:

Government intervention refers to any legal action undertaken by a governing authority aimed at influencing public decisions to enhance the social welfare of a nation (54). It takes many forms, including administrative and judicial monitoring, and is designed to ensure that controlled companies adhere to set norms and standards (55). In recent years, as global attention to occupational safety and health has increased, government intervention has been recognized as a key external control mechanism in ensuring operators' safety behavior (4). This is particularly critical in high-risk industries such as construction, manufacturing and mining, where government intervention is seen as a vital factor in maintaining operational safety (56). Wang et al. (49, 50) found that government supervision in China's mining industry provided operators with clear behavioral guidelines, which are associated with accident prevention and improved overall safety performance. Similarly, in the special equipment industry, the Chinese government has introduced relevant laws and regulations (such as Measures for the Supervision and Management of Personnel Operating Special Equipment) aimed at reducing accident rates and ensuring operators adhere to safety protocols.

However, although the government has promulgated these regulations, accidents continue to occur annually, raising questions about whether the current regulatory approach should evolve in response to social development. This raises critical questions about whether existing regulatory approaches are sufficient or need to evolve in response to societal and industrial changes. More importantly, government intervention may have dual effects. On one hand, it can induce stress or negative emotions among operators, potentially affecting their wellbeing (57). On the other hand, safety campaigns, training mandates, and inspection systems can raise safety awareness, foster positive safety attitudes, and encourage individuals to channel their emotion-focused coping strategies into more constructive and compliant behaviors. Therefore, based on the above discussion, we propose the following hypothesis:

This study employed quantitative methods to collect data, with the goal of providing a more comprehensive and accurate understanding of the associations between stressors and individuals' behavior. The target sample for this study consisted of special equipment operators who has the at least 1 year working experience in China, to ensure sample diversity and statistical power. Furthermore, for ethical reasons, all volunteers are required to sign an informed consent form to confirm their comprehensive understanding of the experiment's objective, methods, and potential dangers.

This work employed a variance-based partial least squares structural equation model (PLS-SEM), with data analysis conducted using Smart-PLS software version 4.1.0.3 (SmartPLS GmbH, Monheim am Rhein, Germany), which provides extensive computational and modeling capabilities, along with professional assistance (64). Additionally, PLM-SEM does not need any distribution assumptions, and maximizes the explanatory variance of the proposed model (65) and enables users to access more intricate models with many variables, indicator constructs, and structural routes (66).

Following the two-step approach, this study first assessed the measurement model, and then the structural model will be provided. To assess the measurement model, the confirmatory factor analysis (CFA) was used to examine internal consistency, and construct reliability and validity. Cronbach's α and compound reliability above 0.7 were used to estimate internal consistency and structural reliability (67). Convergent and discriminant validity were used to evaluate construct validity. To demonstrate convergent validity, the composite reliability (CR) must exceed 0.7, and the average variance extracted (AVE) should surpass 0.5 while being lower than the corresponding CR (68). In the second step, the bias-corrected bootstrapping approach is utilized to test the suggested structural model and assumptions through 5,000 repetitions. All tests in this study were two-tailed, and a p-value of less than 0.05 was statistically significant.

To authors' knowledge, this is the first academic study focusing on the special equipment industry in China, with particular emphasis on the stressors, psychological states, and behaviors of special equipment operators. The findings of this research will serve as a valuable reference for other scholars interested in the special equipment industry or the wellbeing and performance of special equipment operators.

Besides, this study enriches and extends the application of the Transactional Theory of Stress (TTS) within the context of special equipment operators in China. By examining multiple stressors of low social status, harsh working environments, physiological fatigue, and responsibility pressure, it addresses a gap in the literature regarding how these stressors are associated with operators' appraisals, coping strategies, and subsequent safety behaviors. The developed model demonstrated strong predictive power in explaining the safety behaviors of special equipment operators under various stress conditions.

Moreover, the research provides novel insights into the mediating roles of emotion-focused coping between threat appraisal or harm appraisal and safety behavior, as well as problem-focused coping between challenge appraisal and safety behavior in the sector of special equipment operator, thereby deepening theoretical understanding of coping mechanisms in high-risk occupational settings.

Finally, by incorporating government intervention as a moderating variable, this study highlights how external environmental factors are associated with the relationship between coping strategies and safety behaviors, thereby expanding the scope of transactional stress theory and offering new theoretical perspectives for future research.

This study offers several practical implications for industry practitioners and policymakers in the special equipment sector. First, by identifying key stressors such as low social status, harsh working environments, physiological fatigue, and responsibility pressure, organizations and government can develop targeted interventions to alleviate these pressures, thereby enhancing operators' psychological wellbeing and safety performance. For example, organizations can reasonably arrange work and rest schedules to ensure that operators are not subjected to prolonged periods of fatigue, thereby reducing their threat perception. Moreover, given the critical role of operators in the special equipment industry, government authorities could consider adopting professional title recognition and qualification systems, similar to the certification framework for construction engineers, to enhance the social status of these workers. Such measures can help alleviate stress caused by perceived low social standing and foster a more motivated and psychologically healthy workforce.

Second, the findings emphasize the importance of fostering effective coping strategies, particularly problem-focused coping and emotion-focused coping. Organizations should provide training and resources that help operators develop these coping mechanisms. For example, promoting problem solving skills, encouraging proactive communication, and offering stress management workshops can empower operators to handle work-related challenges more effectively. At the same time, emotional support systems, such as peer support groups, mental health hotlines, or access to counseling services can strengthen emotion-focused coping, helping operators regulate their emotional responses to stress. Together, these strategies contribute to improved safety behavior and overall wellbeing in high-risk working environments.

Third, the moderating role of government intervention suggests that policymakers should carefully design regulations and support systems that empower operators without undermining their personal coping efforts. Balanced and context-sensitive government policies can promote a safer and more supportive working environment. For instance, enforce reasonable labor standards, including limits on overtime. Or launch public welfare campaigns to improve operators' public image and social recognition.

First, this study focused on four specific stressors of low social status, harsh working environment, physiological fatigue, and responsibility pressure. However, other relevant stressors may also exist. Future research could adopt qualitative methods to explore additional or emerging stressors affecting special equipment operators.

Second, this study treated operators as a homogeneous group. While this approach provides generalizable insights, the category of special equipment operators includes 11 different types of roles. Future studies could conduct subgroup analyses for each category to generate more targeted and actionable findings.

Third, this research examined government intervention only as a moderating variable between coping strategies and safety behavior. Future studies could further explore the role of government intervention at various stages of the stress-coping-safety behavior process, helping to identify where regulation is most effective or lacking. Additionally, government intervention encompasses multiple dimensions. For example, legally enforced restrictions vs. mechanisms for protecting workers' rights. These different forms may be associated with varying outcomes, and future studies should consider disaggregating and analyzing their individual impacts.