Purpose – Lean is often described as a prerequisite for achieving high operational efficiency through the elimination of waste. At the same time, warehouse operations are rarely free from inefficiencies, interruptions, or non-value-adding activities. Despite this, some warehouses continue to maintain remarkably high performance levels. This creates a paradox between lean theory and operational practice. Therefore, the purpose of this study is: To identify which conditions can contribute to high operational efficiency in a warehouse environment where lean waste has only been partially eliminated. To fulfil this purpose, the following research questions were formulated:

[1] Can a warehouse maintain high operational efficiency despite the presence of waste? [2] Which conditions contribute to maintaining high operational efficiency despite the presence of waste in warehouse management?

Method – The study was conducted as a single-case study at a large manufacturing company’s distribution warehouse operated by a third-party logistics provider. An abductive research approach with primarily qualitative methods was applied. To answer the study’s purpose and research questions, triangulation was conducted through interviews, observations, anddocument studies. Semi-structured interviews were carried out with employees in different operational roles, while observations within the warehouse environment enabled identification of operational behaviours, movement patterns, and waste-related activities in real time.

Findings – The study identified several lean wastes within the warehouse operation, including unnecessary transportation and movement, excess inventory, rework, and underutilized creativity. Despite the presence of these inefficiencies, the warehouse maintained a very high operational efficiency level of 97–99.8%. The findings show that waste did not appear to reduce operational performance to the extent suggested by lean theory. Instead, the organization compensated through other supporting conditions. Five central conditions were identified: experienced employees, informal work practices, coordination and communication, continuous improvement efforts, and workload levelling. The findings therefore suggest that high operational efficiency can be achieved even in the presence of wastes, thereby challenging the assumption that extensive lean implementation is a prerequisite for efficiency.

Conclusions – The study contributes both theoretically and practically. Theoretically, it nuances existing lean research by demonstrating that operational efficiency can be maintained even when lean principles are not fully implemented. Practically, the study provides insight into how warehouse operations may compensate for inefficiencies. This is particularly relevant for complex warehouse environments where complete lean implementation is difficult to achieve.

Limitations – The study is limited to a single distribution warehouse connected to a large manufacturing company and operated by a third-party logistics provider. Furthermore, the study focuses solely on warehouse operations and excludes upstream and downstream processes.

Keywords – Lean warehousing, operational efficiency, lean waste, logistics, lean principles, warehouse flow, operational performance.