###### Abstract
In the early 2000s, several organizations attempted the simultaneous adoption of both methodologies. The integration of LM and SS, known as lean Six Sigma Manufacturing (LSSM), offers a powerful strategy that provides better results in any discipline over individual one [6]. [PERSON] [12] showed that a strategy based only on the application of SS would overlook three benefits that LM would bring, i.e., inventory reduction, processing speed and short-term economic benefits, owing to the time required for learning the methodology, data collection, analysis and application of techniques. LSSM drives process improvement, increasing processing speed and ensuring high-quality outputs, to meet customer satisfaction [13]. Since customer satisfaction is directly related to the profit obtained by the organization [14], the implementation of the LSSM methodology can be considered a part of the business strategy. Currently, the LSSM has become the leading strategy for business improvement and has been effectively implemented across a wide range of businesses. An increasing number of studies indicate that LSSM has substantially contributed to the success of numerous companies in different sectors worldwide. For instance, [PERSON] et al. [15] reported the successful convergence of LM and SS in an aerospace company. The implementation of LSSM reduced waste inventory, production and labor costs, resulting in a substantial increase in sales from USD 30 to 205 million per year. [PERSON] et al. [16] proposed an LSSM approach with a specific focus on value stream analysis for a local manufacturing company in Ohio (USA). The case study demonstrated how this company can substantially reduce costs by USD 0.6 million per year. [PERSON] et al. [17] adopted an LSS framework that incorporates environmental considerations to simultaneously reduce defects and minimize environmental impacts in an Indian automotive manufacturing company. Deployment of the LSSM framework reduced the internal defects from 16,000 to 6000 ppm and the environmental impacts from 42 to 33 Pt. The LSSM has also been successfully implemented in a wide variety of sectors such as electrical [18; 19], casting [20; 21], construction [22; 23], food engineering [24; 25], education [26],communications [27], energy [28], healthcare [29], even government services [30], and many other. [31; 32; 33]. However, despite its proven effectiveness, there are still numerous potential sectors suitable for LSSM implementation that, for a variety of reasons, have not yet adopted these business strategies or are progressing very slowly. One such example is the chemical sector, particularly chemical manufacturing. It is noteworthy that the influence of LSSM on the production of chemicals is not prominent. Indeed, the literature shows that research on the implementation of LSSM in the chemical sector is very limited, especially when compared to the extensive studies focused on non-chemical sectors. Therefore, this sector has yet to fully explore and harness the benefits of LSSM. This assessment raises the following research questions:  
1. What is the trend and actual situation of LSS applied to manufacturing chemicals? 2. What are the motivations or factors driving the adoption of LSS in the chemical manufacturing sector? 3. What factors contribute to the limited adoption of LSS by chemical manufacturing companies? 4. What is the future research direction for chemical manufacturing companies after the LSSM implantation? According to the U.S. Bureau of Labor Statistics, the number of establishments in chemical manufacturing was 23,177 at the end of 2022 in the USA [34], representing 8% of all manufacturing facilities, while the European Chemical Industry Council registered more than 61,000 chemical companies in Europe [35], which means 2.3% of its total. Given the current situation in the international market and the extensive use of chemical products in multiple fields such as food, energy, health, agriculture, etc., the chemical manufacturing sector represents a clear example of customer service.