Carbon Footprint Assessment of Lubricant Products: A Case Study in Taiwan

1. Introduction

Living within planetary boundaries, i.e., the Earth Limits [1], requires achieving the ambitious goal of net-zero throughout the economy. Therefore, industries across sectors are advised to reevaluate their operational and supply chain frameworks in line with the United Nations Sustainable Development Goals (SDGs), while also addressing pressures from consumer markets, regulatory requirements, and supply chain resilience. In modern industry and transportation sectors, lubricants are essential for operating machinery and mechanical systems, as they reduce friction, dissipate heat, prevent wear, and ensure operational reliability [2]. Advanced lubricating oils are made from base oils and blended with chemical additives to meet grade-specific requirements [3]. These oils are widely used in automotive, industrial, marine, and aviation applications.

The global lubricant market was valued at $157.6 billion in 2021 and is projected to reach $182.6 billion soon [4]. In 2017, approximately 4.3 million tons of lubricating oils were placed on the EU28 market [5], with 1.6 million tons of waste oils collected, representing 38% of the total [2], despite sustainability discourse. In Taiwan, the market size is estimated to be over 300 million liters in 2025 and is expected to reach 320 million liters by 2030 [6]. Aiming to achieve a greener world, the Joint Research Center (JRC) of the European Commission has recently officially designated “lubricants” as a priority product under the Eco-design for Sustainable Products Regulation (ESPR) [7] and recommends strict measures for the treatment of waste oils, as they are classified as hazardous waste [2]. The Waste Framework Directive required manufacturers to provide additional labeling, to comply with record-keeping guidelines, and to monitor and control hazardous waste from cradle to grave [8]. This policy signals that lubricants are no longer seen merely as “chemical products” but as key decarbonization tools with strategic value in energy and climate policy. In recent years, more countries have established increasingly stringent environmental regulations. For example, Germany's “Blue Angel” [9], one of the world's earliest environmental labeling systems, focuses on reducing emissions, avoiding the accumulation of ecological toxicity, and promoting sustainable resource use for lubricant products. The EU Ecolabel [10] places greater emphasis on specific criteria such as biodegradability, low toxicity, and environmental friendliness toward aquatic systems. Meanwhile, the United States Environmental Protection Agency (EPA) requires components such as marine propulsion systems and deck equipment that may come into contact with water to use Environmentally Acceptable Lubricants (EALs) [11], characterized by adequate biodegradability, low aquatic toxicity, and low bioaccumulation potential. The primary objective is to reduce the risk of marine and coastal ecosystem pollution caused by lubricant leakage. However, a report by Raj Shah et al. (2024) notes that “bio-no-tox” characteristics (i.e., low ecological toxicity and biodegradability) or EAL criteria mainly focus on environmental protection rather than climate protection [12]. While they align with United Nations SDG 3 (Good Health and Well-being) and SDG 6 (Clean Water and Sanitation), they do not inherently equate to “sustainability.” Future lubricant development will therefore depend not only on performance in terms of friction, wear, and thermal stability, but also on compliance with global requirements for environmental protection and climate action.

Lubricants play a crucial role in achieving energy-saving and carbon-reduction targets in the manufacturing and transportation sectors, yet “sustainable lubrication” is not universally defined. To guide decision-making in that endeavor, this study attempts to conduct a carbon footprint assessment of several lubricant products to identify the “environmentally friendly” or environmentally acceptable bio-lubricants. To be considered environmentally friendly, a lubricant must meet certain criteria, including US EPA standards and EU Ecolabel requirements. According to Pichler et al., (2023) [13], these criteria include high biodegradability, renewable origin, and low toxicity. They must demonstrate rapid biodegradation through standardized OECD and ASTM tests, contain a significant proportion of renewable carbon sources, and pose minimal risks to humans and ecosystems, as assessed by toxicity and bioaccumulation. In addition, sustainable lubricants should be produced at scale using environmentally responsible processes. Emerging solutions include bio-based oils, microbial-derived materials, biopolymers, and advanced lubrication technologies, while complementary practices such as reducing lubricant use, adopting recyclable packaging, and minimizing harmful additives further enhance their environmental performance. To maintain operational performance, lubricant oils are periodically replaced as their quality degrades. Once they become unsuitable for further use, they are discharged as waste lubricant oil (WLO), which must then be re-refined or recycled into other oil products. Mismanagement of oil waste from these lubricants has detrimental environmental consequences, including contamination of air, soil, and water [5]. Used lubricating oil can significantly pollute the environment, affecting aquatic organisms and human health because of its toxicity and carcinogenicity [3]. Recycling WLO offers many environmental benefits, including reducing the need for harsh chemicals to clean up oil spills and providing an alternative energy source [2].

Taiwan passed the Climate Change Response Act in February 2023, explicitly setting a net-zero emissions target for 2050 and incorporating mechanisms for managing carbon footprints and product labeling. The Act also allows for the prohibition or restriction of the manufacture, import/export, use, and emissions of high-carbon products. In addition, Taiwan's Ministry of Environment has implemented a product carbon footprint labeling system since 2010, which is the only carbon labeling scheme in the world officially issued and managed by a government authority. Since 2014, the government has also promoted a carbon reduction label, and to obtain it, products or services must achieve at least a 3% reduction in their carbon footprint within five years. Although Taiwan's labeling system is voluntary, its integration with government green procurement policies has made it a key strategic tool in advancing Taiwan's net-zero goal, particularly under the initiative of “Net-Zero Green Living.” Both the carbon footprint label and the carbon reduction label issued by Taiwan's Ministry of Environment require the use of officially announced product category rules (PCRs) for environmental or carbon footprints, as well as verification by accredited certification bodies and the issuance of independent third-party verification statements prior to application. The purpose of the carbon footprint labeling system is twofold: for enterprises, it encourages the identification of carbon emission hotspots across the full life cycle of products or services and promotes carbon management and reduction; for consumers, it provides carbon footprint information as a reference for purchasing decisions, thereby encouraging changes in consumption behavior and lifestyles and facilitating the transition toward the net-zero goal. Over the last decade, researchers have studied low-environmental-impact lubricants, and many products are now available on the market [13]. In line with Taiwan's sustainability ambitions, this study assesses the carbon footprint of two representative automotive lubricant products, LB5126777 and LB5168477, from a case company. The company has actively invested in the research and development (R&D) of low-carbon products and placed a strong emphasis on consumer communication. It holds a high market share in the lubricant market [14], making it important to the sector's sustainability initiative. Recently, many studies, including Cabrera-Escobar et al. (2025) [2], Ishizaki & Nakano (2018) [15], Pichler et al. (2023) [13], and Shan et al. (2023) [4], have begun exploring the environmental impacts of these oils, and a few have assessed their carbon footprints to identify environmental hotspots. Therefore, this study is among the first of its kind in Taiwan to combine an LCA-based carbon footprint comparison of automotive lubricant products with an implemented, third-party-verified eco-design intervention. LCA is a robust methodological and decision-making tool widely adopted to assess environmental impacts across a product's life cycle and to improve global sustainability design [16,17]. The results from this study can serve as a benchmark for identifying improvement opportunities and supporting the future development of low-carbon lubricant products with enhanced environmental performance, advancing toward the net-zero goal.

Beyond its methodological contribution, this study speaks directly to the broader role of product carbon footprint (PCF) measurement within corporate sustainability practice. As environmental, social and governance (ESG) reporting frameworks and mandatory or voluntary climate-disclosure regimes expand globally, quantified and independently verified PCF data are increasingly used by manufacturers as evidence of environmental performance, both for external ESG-related accountability (customer and investor disclosure, supply chain carbon reporting) and for internal managerial decision-making (e.g., prioritizing eco-design investments and tracking progress toward corporate net-zero targets). Third-party verification, as applied to both products in this study under Taiwan’s PCF and carbon-reduction labeling schemes, is what confers credibility on such data for these accountability purposes, distinguishing verified carbon-footprint figures from unverified self-reported estimates. By pairing a comparative PCF assessment with an implemented and independently verified eco-design intervention, this study illustrates how PCF quantification can function as a decision-support tool that links measured environmental performance to a concrete managerial action and its documented, verified outcome, offering a transferable template for how lubricant and other manufacturers can use verified carbon footprint information to support sustainability accounting, ESG-related accountability and therefore net-zero decision-making.

2. Materials and Methods

LCA (ISO 14040, 2006) is a widely used decision-making tool for assessing the environmental impacts of products [17]. It assesses resource use and overall environmental impacts throughout a product or service’s life cycle, emphasizing transparency and a scientifically rigorous approach [16]. This study employs a cradle-to-grave approach to assess the environmental footprint of two representative automotive lubricant products, designated LB5126777 and LB5168477. These products account for a significant share of Taiwan's automotive lubricant market. The LCA framework used in this study follows the guidelines in ISO 14040, ISO 14044, and ISO 14067, covering the four standard phases: goal and scope definition, life cycle inventory (LCI), impact assessment, and interpretation [18].

1.1. Goal, Scope and Functional Unit

The primary objective of this study is to quantitatively assess and compare the CF of two representative automotive lubricant products and to evaluate the feasibility of incorporating recycled materials into packaging design, referred to herein as eco-design. The assessment involves comprehensive data analysis of the case company; therefore, no primary experimental testing or laboratory preparations were conducted. This study's novelty lies in linking a comparative CF assessment of two automotive engine oil products with an implemented packaging eco-design intervention, enabling decision-makers to redesign manufacturing processes to achieve net-zero goals, ceteris paribus. It follows the ISO 14067 carbon footprint standard and Taiwan's Ministry of Environment “Guidelines for Product Carbon Footprint Management” [19], and meets the requirements of the published Product Category Rules (PCR) for “lubricants” [20]. We carried out the carbon footprint inventory and calculations for the target products and obtained third-party verification to secure carbon labels issued by Taiwan's Ministry of Environment.

The functional unit (FU) of this study is defined as 1 kg of lubricant oil within the system boundary considered. The primary activity data underlying the eco-design comparison were originally compiled per declared unit (one 1 L bottle), consistent with the carbon-reduction-label application. These per-bottle data were converted to the functional-unit basis by dividing by the product density (0.849 kg/L; Table 1), so that 1 bottle (1 L) corresponds to 0.849 kg of lubricant. The FU follows the ISO 14067 carbon footprint verification for Product Category Rules (PCR) [21]. PCRs provide standardized methodological requirements, based on ISO 14025 and ISO 21930, for defining system boundaries, data quality, assumptions, and reporting procedures to ensure consistent and transparent LCA and Environmental Product Declaration (EPD) development for specific product categories [22]. Table S1 in the supplementary materials describes the allocation process. Data quality validation follows the validation described in section 2 of the supplementary file. We then submit the data to third-party validation, as described in section 3 of the supplementary file. The present study adopts comprehensive system boundaries encompassing five life-cycle stages: raw material acquisition, manufacturing, distribution and sales, use, and end-of-life treatment. These boundaries also include production processes at the target lubricant manufacturing facility and upstream activities of the plastic bottle supplier. Figure 1 illustrates the life-cycle process flow for the target lubricating oils, and Figure 2 presents the system boundary for the 1 L HDPE plastic container used for both products. Based on these defined system boundaries, we systematically collected and compiled relevant activity data.

1.2. Life Cycle Inventory Analysis

We collected primary data from our case company. These data include detailed information on raw material inputs, manufacturing processes, energy consumption, and logistics activities. For imported base oils and additives, supplier-specific upstream production data were unavailable; therefore, we used secondary inventories from recognized sources. This study covers the inventory period from 1 January 2021 to 31 December 2021, representing a one-year assessment to quantify the direct and indirect greenhouse gas emissions associated with producing the target lubricant products. The life cycle inventory data were categorized into five stages: raw material acquisition, manufacturing, distribution and sales, use, and end-of-life treatment. The raw material acquisition stage encompasses all input materials required to produce the target products, such as base oils, additives, auxiliary materials, and plastic containers. The collected inventory data include material types, quantities, supplier locations, and associated transportation modes. The manufacturing stage covers blending and filling lubricants, as well as producing plastic containers. The inventory includes quantities of primary, secondary, and auxiliary materials; energy consumption from electricity, water (including cooling water), and natural gas; fugitive emissions such as refrigerant leakage and methane emissions; production output and inventory levels; as well as waste generation and management, including packaging waste, domestic waste from employees, and industrial waste with corresponding treatment and transportation processes. The distribution and sales stage involves transporting the product from the manufacturing facility to three regional warehouses in northern, central, and southern Taiwan. Transportation distances and shipment quantities for each warehouse were individually determined and included in the carbon footprint assessment

According to the referenced PCR, the use stage refers to consumers applying lubricants to engine components. Because product use requires no additional energy or auxiliary material inputs, the associated emissions were considered negligible. The end-of-life stage includes treating waste lubricants and packaging containers. For waste lubricating oil, data from Taiwan’s Environmental Protection Administration indicated that approximately 275,000 metric tons were generated in 2020, of which 248,000 tons were recycled, 4,000 tons were incinerated, and 23,000 tons were treated within factories. Under a conservative assumption, this study considers all internally treated waste lubricating oil as ultimately incinerated, resulting in a recycling rate of 90.18% and an incineration rate of 9.82% for non-recycled waste lubricating oil. For waste containers, based on the recycling statistics reported in reference [23], we assumed a recycling rate of 75.43%, with the remaining 24.57% incinerated.

1.3. Carbon Footprint Assessment

For calculating the product carbon footprint, all non-excluded items within the product life cycle must first be calculated individually, then converted to carbon dioxide equivalents (CO₂eq), and finally aggregated. Equation 1 details the calculation process followed in this study.

Carbon emissions (CO₂eq) = Activity data × Emission factor × GWP value

The emission factors used in this study are primarily sourced from Taiwan's Ministry of Environment Product Carbon Footprint Information System [24], SimaPro (9.0.4.2, PRé Sustainability), IPCC AR6 (2021) [25], supplier-specific inventory coefficients, and third-party-verified product carbon footprint reports. The GWP (Global Warming Potential) values refer to the warming potential of greenhouse gases, and this study adopts the IPCC Fourth Assessment Report (2007) values in accordance with Taiwan's Ministry of Environment regulations.

1.4. Product Eco-Design Process

According to the regulations of Taiwan’s Ministry of Environment, products that

have obtained a carbon label and achieve a minimum 3% reduction in carbon footprint within five years through implemented reduction measures are eligible to apply for a carbon reduction label. Therefore, this study evaluates the potential carbon-reduction strategies using an eco-design approach. Of the two products assessed in this study, the eco-design intervention was implemented and verified for LB5126777, the higher-volume flagship product: the 1-L HDPE plastic bottle containing CPC Racing Grade C3/SN Fully Synthetic Automotive Engine Oil 5W/30 (Motor Oil 5W/30), which was assessed for opportunities to reduce its carbon footprint and for carbon-reduction label application. Table 1 shows the product specifications.

1.1.1. Baseline Scenario and Inventory Period

This study uses the carbon label product as the baseline. After the target product completes eco-design improvements and enters mass production and sales, we conduct a carbon footprint inventory for the reduced-carbon product. Figure 3 shows the inventory periods for the carbon-label and carbon-reduction-label products. For the baseline stage of the target product, the inventory period covers January to December 2021, representing one year of activity data. For the carbon-reduction-labeled product, the inventory period after production completion and commercialization covers June 2023 to May 2024.

1.1.2. Implementation of the Eco-Design Process

After selecting recycled HDPE pellets and the plastic bottle manufacturer, the team conducted a series of validation tests to ensure the recycled packaging materials met the required quality and performance specifications. The validation process included bottle manufacturing trials, empty-bottle performance testing, filling-line compatibility testing, and transportation simulation testing. Procurement and full-scale production were initiated only after all validation procedures were successfully completed. The implementation procedures are described as follows.

• Empty bottle performance test: The empty-bottle test was conducted to evaluate the mechanical strength and durability of recycled HDPE bottles. The test included buckling resistance evaluation, drop tests from heights of 1 m and 3 m, and durability assessments.
• Filling process compatibility test: The filling test was performed to verify the compatibility of recycled HDPE bottles with the existing lubricant packaging process. The evaluation included bottle filling, cap sealing, inkjet printing, carton packaging, film wrapping, and pallet stacking operations. The team conducted a simulated load-bearing test over eight days. No abnormalities were observed during the test, confirming that the recycled HDPE bottles met the operational requirements.
• Transportation simulation test: The transportation test was conducted to evaluate packaging integrity under actual distribution conditions. The packaged products were transported to the northern warehouse, stored for 6 days, then transported to the southern warehouse, and finally returned to the manufacturing facility. We inspected cartons and bottles individually throughout the process. In addition, we inverted bottles to assess leakage resistance. We observed no damage, deformation, or leakage, indicating that the recycled HDPE packaging passed the transportation validation test.

1.5. Study Limitations

This study follows the cut-off criteria defined in the PCR for “lubricants” approved by Taiwan's Ministry of Environment in 2023 [23], which allow excluding processes contributing less than 1% of the total environmental impact, provided the cumulative excluded contribution does not exceed 5%. Based on these criteria, several limitations were identified:

• Raw material acquisition stage: Detailed upstream data for some imported raw materials (e.g., base oils manufacturing) were unavailable due to supplier data limitations. Therefore, we estimated certain upstream manufacturing emissions from PCR or other trusted sources.
• Manufacturing stage: Some minor emission sources, including specific consumables, maintenance materials, labeling materials, non-production vehicle activities, administrative activities, and certain supplier-related emissions (e.g., refrigerant use and wastewater treatment at the plastic bottle production facility), were excluded due to limited data availability or their expected negligible contribution
• Distribution and sales stage: Only transportation from the manufacturing facility to regional warehouses was included. We excluded downstream transportation to customers because distribution routes are complex and logistics data are limited.
• Use stage: Lubricant losses through evaporation or consumption during use were not considered according to the PCR/PEFCR assumptions [24]. The products were assumed to operate under normal conditions, without significant material loss, before end-of-life treatment; therefore, emissions from the use phase are assumed to be zero.

3. Results and Discussion

3.1. Carbon Footprint Assessment Results

This study assessed and compared the cradle-to-grave life cycle of two representative automotive engine oil products, LB5126777 and LB5168477, both packaged in 1 L HDPE bottles, using a FU of 1 kg of lubricant. Table 2 and Figure 4 present the life-cycle-stage breakdown of the CF for both products. The total CF is 1.463 kg CO₂ eq/kg for LB5126777 and 1.449 kg CO₂ eq/kg for LB5168477, a difference of less than 1%, indicating that the two formulations have a comparable overall footprint despite differences in their additive packages and base-oil mixes. For both products, raw material acquisition is overwhelmingly the dominant contributor, with 1.364 kg CO₂ eq/kg (93.2%) for LB5126777 and 1.367 kg CO₂ eq/kg (94.3%) for LB5168477. Manufacturing contributes 0.039 kg CO₂ eq/kg (2.7%) for LB5126777 versus 0.018 kg CO₂ eq/kg (1.2%) for LB5168477; distribution and sales contribute 0.017-0.018 kg CO₂ eq/kg (about 1.2%) for both products; and end-of-life treatment contributes 0.043 kg CO₂ eq/kg (2.9%) for LB5126777 and 0.046 kg CO₂ eq/kg (3.2%) for LB5168477. Emissions from the use stage are negligible for both products, consistent with the PCR assumption that use requires no additional energy or material inputs. In this study, we also did not assess engine performance or potential fuel-saving benefits associated with friction reduction during lubricant use. Expressed on a per-liter basis, these results correspond to approximately 1.24 kg CO₂ eq/L for LB5126777 (density = 0.849 kg/L) and 1.24 kg CO₂ eq/L for LB5168477 (density = 0.8534 kg/L). Both values are lower than the 1.65 kg CO₂ eq/L reported by Ishizaki and Nakano [15] for a synthetic lubricant. This may reflect differences in formulation, base-oil sourcing, and system-boundary scope; notably, their assessment excluded disposal and recycling, whereas the present cradle-to-grave study includes end-of-life treatment of both the waste lubricant and the packaging. Nonetheless, the two estimates are of comparable magnitude and support the plausibility of the results obtained here.

3.2. Emissions Hotspot Analysis.

Hotspot analysis of the two products' CF (Table 3) confirms that raw material acquisition, specifically the base oils used in each formulation, is the principal source of emissions. For LB5126777, Base Oil F and Base Oil G together contribute 49.80% of the total product carbon footprint (28.00% and 21.80%, respectively), and Mineral Oil A contributes a further 11.24%. For LB5168477, Base Oil F alone accounts for 49.72% of the total footprint, with Base Oil G contributing a further 9.69% and Mineral Oil C contributing 6.92%; this greater reliance on a single base oil reflects the different additive and viscosity-modifier package used in the 10W/40 formulation relative to the 5W/30 product.

The 1 L HDPE plastic bottle is the second-largest hotspot for both products: its two-constituent material/process contributions (Plastic Bottle A and Plastic Bottle B) together account for 14.83% of the total footprint for LB5126777 (7.48% and 7.35%) and 15.05% for LB5168477 (7.59% and 7.46%). This consistent, approximately 15% packaging contribution across both products aligns with the general scale effect observed for small-volume lubricant packaging, where the mass of packaging material required per unit of lubricant delivered is comparatively high relative to larger-format industrial packaging. Together, base oils and packaging materials account for 75.87% of the LB5126777 footprint and 81.38% of the LB5168477 footprint, underscoring that upstream decisions on base-oil sourcing and packaging material selection offer the greatest leverage for reducing the carbon footprint of both products.

3.3. Eco-Design Process of the Recycled Plastic Bottle Packaging

This study developed a carbon-reduction design for LB5126777 (“Grade 5W/30 Fully Synthetic Automotive Engine Oil”) by replacing the original 1-liter HDPE plastic bottle with packaging produced from 100% recycled HDPE (rHDPE); this intervention was not applied to LB5168477 in the present study. Table 4 and Figure 5 compare carbon footprints before and after implementing the reduction strategy.

The total life-cycle CF decreased from 2.031 to 1.870 kg CO₂eq/kg, a net reduction of 7.89% (Table 4, Table 5). This total change results from three stage-level movements of different origins. Raw-material-acquisition emissions fell from 1.893 to 1.723 kg CO₂eq/kg (−8.96%) by replacing virgin HDPE with recycled HDPE packaging; because this is the only stage in which the eco-design intervention altered an input, this decrease represents the effect directly attributable to the packaging intervention. Manufacturing-stage emissions rose from 0.054 to 0.065 kg CO₂eq/kg (+19.57%), an increase unrelated to the packaging change; and distribution-stage emissions fell from 0.024 to 0.022 kg CO₂eq/kg (−5.00%) owing to a shift in the mix of regional warehouses served during the later period, likewise unrelated to the packaging intervention. Use-stage and end-of-life emissions were unchanged. Isolating the packaging effect from these two confounding, period-specific changes by holding manufacturing, distribution, use, and end-of-life emissions at their baseline-period values and substituting only the reduction-scenario raw-material value, gives an estimated total of 1.861 kg CO₂eq/kg, an isolated reduction of 8.35% relative to the 2.031 kg CO₂eq/kg baseline. This isolated estimate is consistent with the 8.96% reduction observed directly at the raw-material-acquisition stage and indicates that the packaging intervention alone would account for a somewhat larger reduction than the 7.89% net change actually observed. The 7.89% figure should be read as the net change observed between the two assessment periods, not as an isolated measure of the packaging intervention’s effect.

During the carbon-reduction-label inventory period, the increase in manufacturing-stage emissions coincided with lower production output than in the baseline year and higher total plant electricity consumption, which together increased the electricity consumption allocated per unit of product. This study did not investigate the specific cause of the change in production output during this period, and it makes no causal attribution; the change is reported as observed. Despite this increase, the manufacturing stage’s contribution to the total carbon footprint remained relatively limited (Table 4), and, driven predominantly by the raw-material-stage effect described above, the overall life-cycle emissions were still reduced. Figure 6 provides a detailed analysis of emission changes across life-cycle stages, expressed on the same functional-unit basis as Table 4. These findings highlight the effectiveness of recycled packaging materials as a carbon-reduction strategy for lubricant products, and suggest that the same intervention could plausibly be extended to LB5168477 given its similar packaging profile, subject to verification against that product's own baseline and post-intervention inventories.

4. Conclusions

This study applied a cradle-to-grave Life Cycle Assessment, following Taiwan’s Product Category Rules for lubricants, to quantify and compare the CF of two representative automotive engine oil products, LB5126777 and LB5168477, and to evaluate the implemented carbon-reduction eco-design strategy. The total carbon footprint was 1.463 kg CO₂ eq/kg for LB5126777 and 1.449 kg CO₂ eq/kg for LB5168477, a difference of less than 1% despite differences in additive formulation and base-oil mix. For both products, raw material acquisition was overwhelmingly the dominant contributor (over 93% of the total footprint), driven primarily by base oils and, to a lesser extent, mineral oil and the 1 L HDPE plastic bottle; manufacturing, distribution, and end-of-life stages together contributed less than 7% of the total footprint for either product. These findings confirm that, for automotive engine oil products packaged in small-volume retail containers, upstream material sourcing and packaging design represent the greatest opportunities for emission reduction. Building on this hotspot analysis, the study implemented and verified a green-design intervention for LB5126777, replacing the virgin 1 L HDPE bottle with a 100% recycled HDPE (rHDPE) bottle. Following a structured validation process, comprising empty-bottle performance testing, filling-line compatibility testing, and transportation simulation testing, the recycled packaging was confirmed to meet mechanical and logistical performance requirements without compromising product quality. On a FU basis, the reduced-carbon product’s CF after implementation was 7.89% lower than the baseline. Because the baseline and post-implementation inventories were drawn from two different assessment periods that also differed in production output, electricity allocation, and distribution patterns, this net figure combines the packaging intervention’s effect with unrelated period-to-period changes; isolating these confounding effects attributes an estimated 8.35% reduction directly to the packaging intervention itself, consistent with the 8.96% reduction observed at the raw-material-acquisition stage. These results demonstrate that recycled packaging materials constitute an effective, technically validated, and readily transferable carbon-reduction strategy for automotive lubricant products. For the broader lubricant sector pursuing net-zero goals, the findings support three priority actions: adopting renewable electricity and energy-efficient practices in manufacturing; optimizing base-oil sourcing toward lower-carbon, re-refined, or bio-based alternatives; and expanding the use of recycled and circular packaging materials, particularly for small-volume retail formats where packaging-related emissions are proportionally greatest. Future research should extend the eco-design intervention validated here for LB5126777 to LB5168477 and to the case company’s broader lubricant portfolio, and should evaluate the carbon-reduction potential of base-oil substitution strategies alongside packaging interventions.

More broadly, this case study illustrates how a rigorously conducted, third-party-verified PCF assessment can serve as an accountability and decision-support instrument. The verified CF and carbon-reduction-label data reported here provide independently validated evidence of environmental performance that manufacturers can use to support ESG-related disclosure to customers, investors, and regulators, and that managers can use internally to prioritize and justify eco-design investments and to track measurable progress toward corporate and national net-zero commitments. As carbon-footprint and climate-related disclosure requirements continue to expand, the approach illustrated here offers a practical and transferable model for translating product-level sustainability information into managerial action within the lubricant sector and beyond.