Zachary R. Hicks
Kaede Lin
Nathan Tsunoda

Materials

Zachary R. Hicks
DES 40A | Cogdell
16.mar.2023

Introduction

Diabetes is a condition in which the body is either unable to produce insulin (Type 1), or has become resistant to the insulin that it can produce (Type 2) (Sapra and Bhandari).  A wearable insulin pump, as the name describes, is a wearable medical device that patients with diabetes can use to deliver insulin to their bloodstream.  These ambulatory infusion pumps are often used at home and on the go given their portable nature (What is an Infusion Pump?).  Wearable insulin pumps will often operate in concert with a continuous blood-glucose sensor to inform the user when they should administer insulin via the pump.  This whole system greatly reduces the frequency at which patients must manually draw blood and administer insulin shots, leading to a safer and less laborious routine for users (Klonoff et al., Poulson).  In general, wearable insulin pumps consist of several components which are housed within a plastic frame:

1. A disposable plastic insulin reservoir,

2. A motor and screw drive system to pump the insulin,

3. A small computer to control the motor and deliver correct insulin doses,

4. A small display for user feedback,

5. Batteries as a power source,

6. Tubing and plastic needle (often implanted into the abdomen) (Valla).

Note: ‘Tubeless’ pumps do exist and are attached with adhesives directly to the abdomen with an adhesive patch.

Objective: This paper will focus on the raw materials that go into the entire life-cycle of a wearable insulin pump. A product’s life-cycle can be chronologically divided into six distinct phases: raw materials acquisition, product manufacturing, distribution and transportation, use/re-use, and recycling/waste management. This is shown in figure 1 in the appendix.

While all six of these phases will be addressed here, when focusing on the raw materials of this life-cycle, there are three key steps to be considered: materials acquisition, product manufacturing, and the use/re-use and maintenance.  Additionally, excess materials are produced at each of these stages, that if reused or recycled properly, may improve the efficiency at each of the three aforementioned steps.  Due to a lack of publicly available information as to the specific quantities of the materials used in the life-cycle of wearable insulin pumps, many of the aforementioned steps will be discussed in qualitative detail.

Raw Materials Acquisition

Most of the components that comprise a wearable insulin pump are made up of various materials that can be grouped into two broad categories: plastics, metals, and nonmetals. The first step in creating plastics is either through the mining or the drilling for crude oil and natural gas (Brown).  Mining involves digging, scraping, and removal of underground resources, all of which require heavy machinery in need of fuel and routine maintenance (Brown).  An alternative method for accessing these resources is called hydraulic fracturing, a.k.a. ‘fracking.’  Fracking will often use water as the main material to break open earth to access the natural gas and crude oil, in addition to sand and/or aluminum oxide to keep these fractures open (Von Estorff and Gandossi). 

The metals required for these devices are used for structural/mechanical purposes, or as electrical materials in the case of copper for wiring for example. More specifically, some of these metals are also alkali metals, such as those found in batteries.  Steel metal alloys start from iron ore which is mined as hematite or magnetite in its natural state to be further purified and combined with carbon (Mineral Information Institute).  A common carbon source for steel is ‘coke,’ a form of purified coal, which also must be accessed via mining.  Finally, metal additives such as chromium and other nonmetals are also necessary to create stainless steel alloys with medical-grade material properties. 

Product Manufacturing

For plastics, after the raw materials are extracted, the crude oil and natural gas is then taken to a refinery to be converted into ethane and propane respectively.  These products are then further processed into ethylene and propylene at ‘cracking’ facilities (Brown).  Both of these products are then polymerized into resins that are heated and pressurized into plastic pellets which can be injection-molded or extruded to a shape that meet a manufacturer’s needs (Brown).  For example, the plastic housing of an insulin pump or the replaceable insulin cartridge is likely made via injection molding and the plastic cannula via an extrusion process.  While injection molding and extrusions do not need other added materials to create their end-products, these processes do require heat, and thus an energy source.  Another path that the plastics can take is into electronic components such as printed circuit boards (PCB’s).  The base insulating material of a PCB is made from a fiberglass reinforced plastic that is then layered with a conductive metal sheet (Keim).  Electronic components are then mounted to this board, many of which contain metals and nonmetals and are often housed in plastic.  Once programmed, this creates the basis for the miniature computers and/or microcontrollers found within innumerable electronic devices, including the wearable insulin pump.

As alluded to above, the mined and processed metals and nonmetals can be used for both electronic and mechanical means in these devices.  Metals and alloys, once refined, can be forged, extruded, and machined into brackets, fasteners, parts for the motor, and any necessary forms of conductive materials such as copper sheets or wiring.  Once all these components are made they can then be used to assemble the primary components of a wearable insulin pump listed in the introduction.  The batteries in these devices are often small alkaline batteries which generally contain chemicals such as manganese dioxide (MnO2).  After completing assembly the insulin pumps can then be prepared for packaging and transportation.  

Distribution & Transportation

First, before the devices can be transported, they have to be packaged appropriately.  Some components will require sterilization like the metal and plastic cannula and needle set that delivers the insulin to the patient’s abdomen.  According to the FDA, roughly 50% of medical devices in the U.S. are sterilized using ethylene oxide gas.  This is a common method given its ability to clean hard-to-reach areas, and that it is less likely to cause damage to plastics, metals, and glass (Sterilization for Medical Devices).  Other sterilization techniques make use of steam, heat, radiation, and vaporized hydrogen peroxide gas (Sterilization for Medical Devices).  Once prepared, the devices and associated materials are often then packaged and sealed into single-use plastic packaging that keeps the device clean, protected from air flow, light, and moisture (Medical Packaging: Types of Packaging in Pharmaceuticals and the Medical Industry).  After packaging, the pump systems are then shipped to their destinations.  This can be done via truck, train, sea, and air, depending on the scale of the market and size of the company making the pumps.  All of these methods require a fuel source and materials for maintaining these modes of transportation.  For example, trucks require engine oil, transmission fluid, coolant, and powered steering fluid just to name a few.  Once the product has arrived at a destination such as a hospital, doctor’s office, or pharmacy, they can at last be placed in the hands of the patient.

Use/Re-use & Maintenance

Once the patient has their wearable insulin pump, they will need to keep it powered with alkaline batteries and replace the insulin being administered by the pump.  The rate of insulin replacement can vary depending on the device, with some models needing new insulin every 2-3 days, while others claim to last longer.  If the model uses a tube and cannula, this too will need to be replaced regularly- also around every 2-3 days (Christiansen).  One particular tubeless model is single-use, so in this case, the whole pump system has to be replaced after 3 days once it has used all of its stored insulin (Christiansen).  On units that are not single-use, batteries have to be replaced less often than the insulin, but will still drain given the continuous activity required from these pumps.  By one estimate, models will need to have their batteries replaced every 3-10 weeks, depending on usage and type (Important Considerations for Insulin Pump and Portable Medical Designs). Furthermore, if a pump or cannula is not able to adhere correctly to the patient’s body, they may choose to also make use of medical tape around the edges of the device to give it a better hold until it is time to dispose of. 

Recycling & Waste Management

Throughout its production, use, and at the end of a wearable insulin pump’s life, there is waste produced in a multitude of forms.  Given the nature of these devices, they are often classified as biomedical waste and must also be handled carefully because of the needle that they can contain.  These two factors make it difficult to sterilize, reuse, or recycle any contaminated pump materials.  If properly disposed of by the user, sharps waste will be taken to a facility to be sterilized by steam autoclave and then incinerated (Wakelam).  Even if the pump is separated from the cannula by tubing, the pump reservoir should still be disposed of as medical waste, given its contact with bodily fluids.  This complicates the process of disassembly and recycling any of the plastics and electronics within these devices.  According to one report in 2021, none of the current insulin pump companies offer recycling programs for their products within the United States (Hoskins), meaning that many of these devices will end up being incinerated or in landfills (if improperly disposed of).  Some users have taken it upon themselves to disassemble the devices once they are done with them to isolate and best dispose of the different types of plastic, metals, electronics, and sharps (Hoskins).

Conclusion

As with most products, it is clear that there are many more steps in the life cycle of a wearable insulin pump than one might initially expect.  Performing this type of ‘cradle to grave’ analysis is important to address any existing areas of environmental harm and inefficiency in an existing device’s life cycle. Life cycle assessments are especially beneficial when performed while a product is still in development to avoid unnecessary waste and harm to the environment. With regards to wearable insulin pumps, the lack of ability to easily recycle and reuse components within the pump is a cause for concern.  This should be approached in two ways, one from the designers side, wherein the pumps can be made from materials that are easier to recycle, pumps that are easier to disassemble in a manner that can isolate biomedical wastes.  The second being to require companies to offer insulin pump waste collection programs, as these companies are responsible for the existence of the products they sell.

Appendix

Bibliography (MLA 9)

Brown, Natalia. “The Life Cycle of Plastics.” Debris Free Oceans, 31 Jan. 2020, https://debrisfreeoceans.org/the-life-cycle-of-plastics.

Christiansen, Sherry. “Manage Your Diabetes With Wearable Tech.” Verywell Health, https://www.verywellhealth.com/wearable-tech-for-diabetes-4846257. Accessed 14 Mar. 2023.

Important Considerations for Insulin Pump and Portable Medical Designs | Analog Devices. https://www.analog.com/en/technical-articles/important-considerations-for-insulin-pump-and-portable-medical-designs.html. Accessed 14 Mar. 2023.

Joseph, Josh. “Insulin Pumps: Understanding Them and Their Complications.” ALiEM, 11 Dec. 2013, https://www.aliem.com/insulin-pumps-understanding-them-and-complications/.

Keim, Robert. What Is a Printed Circuit Board (PCB)? - Technical Articles. https://www.allaboutcircuits.com/technical-articles/what-is-a-printed-circuit-board-pcb/. Accessed 13 Mar. 2023.

Klonoff, David, et al. Continuous Glucose Monitoring: A Review of the Technology and Clinical Use | Elsevier Enhanced Reader. https://doi.org/10.1016/j.diabres.2017.08.005. Accessed 10 Feb. 2023.

Medical Packaging: Types of Packaging in Pharmaceuticals and the Medical Industry. https://www.thomasnet.com/articles/materials-handling/types-of-medical-packaging/. Accessed 13 Mar. 2023.

Mineral Information Institute - IRON ORE. 17 Apr. 2006, https://web.archive.org/web/20060417160321/http://www.mii.org/Minerals/photoiron.html.

Poulson, Brittany. “Insulin Pump: What It Is, How It Works, and What Types.” Verywell Health, https://www.verywellhealth.com/insulin-pump-6836063. Accessed 7 Feb. 2023.

Sapra, Amit, and Priyanka Bhandari. “Diabetes Mellitus.” StatPearls, StatPearls Publishing, 2022. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK551501/.

Sastri, Vinny R. Plastics in Medical Devices: Properties, Requirements, and Applications. Elsevier Science & Technology Books, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/ucdavis/detail.action?docID=1576659.

Shelke, Namdev, et al. Chapter 7 - Polyurethanes. 2014, pp. 123–44, https://doi.org/10.1016/B978-0-12-396983-5.00007-7.

“Sterilization for Medical Devices.” FDA, Sept. 2022. www.fda.gov, https://www.fda.gov/medical-devices/general-hospital-devices-and-supplies/sterilization-medical-devices.

Valla, Vasiliki. “Therapeutics of Diabetes Mellitus: Focus on Insulin Analogues and Insulin Pumps.” Experimental Diabetes Research, vol. 2010, Jan. 2010, p. 178372. ResearchGate, https://doi.org/10.1155/2010/178372.

Von Estorff, Ulrik, and Gandossi, Luca . An Overview of Hydraulic Fracturing and Other Formation Stimulation Technologies for Shale Gas Production: Update 2015. Publications Office of the European Union, 2015. Publications Office of the European Union, https://data.europa.eu/doi/10.2790/379646.

Wakelam, Laura. “What Happens to Sharps Waste?” Daniels Health, 16 Sept. 2021, https://www.danielshealth.ca/knowledge-center/what-happens-sharps-waste.

What Is an Infusion Pump? | FDA. https://www.fda.gov/medical-devices/infusion-pumps/what-infusion-pump. Accessed 7 Feb. 2023.

Embodied Energy

Nathan Tsunoda
Professor Cogdell
DES 40A
16 March 2023

The Embodied Energy Of A Wearable Insulin Pump

For people diagnosed with diabetes, insulin injections are often a constant recurrence. With the application of modern technology, a wearable, automatic insulin pump can streamline the process. A wearable insulin pump is used in conjunction with a continuous glucose monitor so the pump can automatically deliver insulin to the user at the right times. The energy used over a wearable insulin pump’s life cycle is most environmentally impactful during the phases of acquiring materials, product manufacturing, and distribution. The first step in our product’s life cycle is the acquisition of raw materials.

First and foremost, our product’s life cycle begins with raw materials being extracted from the earth with the help of energy. The main materials that make up a wearable insulin pump discussed in this essay consist of plastic for its outer casing and display screen, epoxy resin, glass fiber, and copper for it’s circuit board. Plastic is a secondary material, commonly created from crude oil. Plastic manufacturing is discussed during the manufacturing stage. Crude oil is extracted from the earth by drilling wells into the ground, and from the pressure applied by pump jacks, the oil flows up to the surface. This is referred to as primary oil extraction. Popular pump jack designs commonly use either an electric motor or internal combustion engine as the prime mover, turning either electric or chemical energy into kinetic energy respectively. Secondary extraction injects either water or gas into the earth to drive oil towards a drilled hole. Both techniques use machinery that utilizes crude oil, chemical energy, in order to drill into the earth’s crust. Statistics show that 25 units of oil-based energy are obtained for every one unit of other energy that is invested to extract it (Nuwer).

The copper present in the product’s circuit board is mined from the earth, as chemical energy from crude oil powers boring machinery that drills holes into hard rock, turning chemical energy into kinetic energy. Energy also goes into manufacturing the explosives that blast and break the rock on site, explosions created by chemical energy. The ore is taken away in “specialized haul trucks, conveyors, trains, and shuttle cars… to the processing site,”  (The University of Arizona) which all likely operate off of fossil fuels; turning chemical energy into kinetic energy. The iron ore is then crushed into smaller pieces by a machine known as a primary crusher, using even more energy. Thermal energy is utilized during a process known as flash smelting, usually powered by coal, as the ore is heated to 1830°F in order to remove other various elements. This produces a supply of concentrated copper. The copper is then refined in a process called electrolysis which uses electrical energy to remove any lingering impurities. The energy used to extract one kilogram of copper is believed to be around 60 megajoules (Elshkaki et al.). Tracking the energy consumption throughout a wearable insulin pump’s life cycle, the next energy intensive step of the cycle is the manufacturing stage. 

Manufacturing plays a large role in a wearable insulin pump’s product’s life cycle, as this step includes both creation of new secondary materials and piecing the final product together. Manufacturing a wearable insulin pump requires plastic which composes the entire outer shell of the product. Plastic is commonly created from crude oil, as its extraction has been discussed earlier. Crude oil is shipped from extracting sites to oil refineries, with the method of transportation most likely utilizing fossil fuels to operate. Chemical energy is turned into thermal energy by machinery as the oil is heated up, where a chemical called naphtha is released. Naphtha is further processed with machinery that reaches high temperatures and high pressures. These machines run off of chemical energy from fossil fuels and electrical energy. These processes produce ethene, which is further processed in high pressures to produce strings of plastic. The strings are grinded into plastic pellets by a machine that turns electrical energy into kinetic energy. Plastic in pellet form increases the flexibility for use in a number of applications. These pellets are then transported by modes that utilize chemical energy from fossil fuels to create movement by kinetic energy to other factories. These factories utilize thermal energy to heat the pellets up to a liquid in order to settle the plastic into a specific mold for a product- in this case an outer casing. The plastic is then cooled to a solid, most likely by a machine using electrical energy. Research shows that producing one kilogram of plastic from crude oil uses 62-108 megajoules (North American Forest Foundation). Manufacturing includes the construction of the internal electronics as well.

The process to manufacture a circuit board is energy intensive. Sheets of woven glass fibers are strengthened with epoxy resin. This new, stronger material is known as FR-4. These sheets are stacked on top of each other with a sheet of copper in between, in a largely automated process as electrical energy powers factory robots to perform work with kinetic energy. Thermal energy is used to heat the sheets up to 340°F. Electrical energy turns to kinetic energy as drills punch holes into the board according to the circuit design. Electrical energy powers machines to add a layer of copper to the surface of the board according to the design of the circuit. Tin lead is applied over the copper to prevent copper’s oxidation and corrosion, increasing its lifespan. The board is then passed through an oven to fuse the tin to the copper, utilizing thermal energy from chemical energy (fossil fuels). Electronic components are glued on by solder paste, either by machine or by hand. The components are then soldered to the circuits (Madehow). After the wearable insulin pump is manufactured, it is distributed to sites where it eventually reaches the hands of end users, as the distributing phase begins.

The energy used to distribute an automatic insulin pump not only includes the method of transportation used to ship the final product, but also includes the energy used to transport materials and sub-components that make up the product, as well as the energy used to package the product. For parts sourced overseas, “the [global] shipping industry uses more than 300 million tons of fossil fuels every year, roughly 5% of global oil production” (Jacoby). According to the United States Department of Transportation, the energy consumed by trucks in the United States during 2019 was 3,487 trillion British Thermal Units. Jet fuel consumed 1,645 trillion, and freight trains consumed 470 trillion. All of these modes of transportation turn chemical energy from fossil fuels into kinetic energy for movement. It is important to note that shipping is present inside each phase of the pump’s life cycle. For example, during the material acquisition phase, oil is shipped from extraction sites to oil refineries which convert the liquid oil into hard plastic. The newly created plastic beads are shipped to manufacturing sites where the plastic is molded to the product’s specifications. It is probable that in the final manufacturing steps these molds, in addition to newly created circuit boards and other components, are shipped to one last manufacturing site that implements all of these parts into one final product. Regarding the packaging of the final product, a standard sized cardboard box requires 1600 kWh of energy to manufacture (Ecobox). Energy is also utilized in the bubble wrap that is used to cushion the product during shipping. Bubble wrap made up of polyethylene (plastic), which starts out in the form of beads. Processes utilize thermal energy from either electrical energy or chemical energy (from fossil fuels) in order to be heated up to form sheets. Electrical energy is used to supply suction to one polyethylene sheet through a hole-punched surface, creating a circular pattern. The second sheet is then laminated to the first sheet, utilizing electrical energy, trapping the air between the two layers (Stanley Packaging). After the final product has been shipped and has reached the hands of the end user, the use phase begins.

The energy used during the use phase of an automatic insulin pump primarily stems from disposable hypodermic needles and AA batteries. Users are to replace needles at infusion sites every 48-72 hours. These hypodermic needles are created from stainless steel sheets, where they are rolled and argon welded to form a pipe shape. Electrical energy is used to stretch the pipe to form its outer and inner diameters. The tip is polished by a high-speed grinding wheel which turns electrical energy into kinetic energy. It is sterilized and packaged in a class eight clean room which utilizes electrical energy for ventilation systems. One company states that all assembly processes are automated, utilizing electrical energy to power machines on the factory floor (Misawa Medical Industry Co., Ltd.). A wearable insulin pump produced by Medtronic requires one AA battery to operate. AA batteries hold chemical energy which is turned into electrical energy. It is estimated that the production of one AA battery costs 1.73 MJ (Hamade et al.), where the battery only holds a mere 0.01 MJ. The product’s final phase is reached after the product has been used and is ready to be disposed of.

The disposal of the wearable insulin pump largely goes to the landfill. This is due to the wide variation of complex electronic materials it is composed of. The printable circuit boards do contain recyclable materials such as copper and FR-4 (epoxy resin and fiberglass), but unique challenges to recover these materials present themselves. For example, metals can be extracted by heating up the circuit board, which utilizes thermal energy, but in turn the FR-4 is incinerated. Chemical extraction of metals on the circuit board using acid also destroys the FR-4. Creative ways to recycle circuit boards are being developed. Disposal of used needles also presents unique energy usages. The medical waste from hospitals is highly regulated and hauled only by certified medical waste disposal companies, whereas household medical waste is not, as medical waste is thrown out with one’s general trash disposal, and then sent to materials recovery facilities. In these facilities, needle-stick injuries are one of the top three injuries reported (Gold). Due to these injuries, instructions are given to dispose of needles in “FDA-cleared sharps containers” made from “puncture-resistant plastic with leak-resistant sides and bottom” (U.S. Food And Drug Administration). These hard plastics only require more crude oil and more energy from oil refineries to manufacture. Hopefully the disposal of both electronic waste and household medical waste will be improved upon in the future.

All in all, the energy used over an automated insulin pump’s life cycle is most environmentally impactful during the phases of acquiring materials, product manufacturing, and distribution. We have seen how the final product is composed of numerous components that all have their own unique life cycle. We can use this information to further engineer similar products' life cycles in order to ease the environmental burden on earth’s natural resources by designing products with materials that have a greater post-disposal use, designing with less energy intensive materials, and reducing both packaging and shipping within all phases of the product’s life cycle.

Bibliography

Ecobox. “How Much Water and Energy Does an Ecobox Save?” Ecobox, 5 Dec. 2018, ecobox.co.za/blog/much-water-energy-ecobox-save/.

Elshkaki, Ayman, et al. “Copper Demand, Supply, and Associated Energy Use to 2050.” Global Environmental Change, vol. 39, July 2016, pp. 305–15, doi:https://doi.org/10.1016/j.gloenvcha.2016.06.006.

Gold, Kathleen. “Analysis: The Impact of Needle, Syringe, and Lancet Disposal on the Community.” Journal of Diabetes Science and Technology, vol. 5, no. 4, July 2011, pp. 848–50, doi:https://doi.org/10.1177/193229681100500404.

Hamade, Ramsey, et al. “Life Cycle Analysis of AA Alkaline Batteries.” Procedia Manufacturing, vol. 43, 2020, pp. 415–22, doi:https://doi.org/10.1016/j.promfg.2020.02.193.

Jacoby, Mitch. “The Shipping Industry Looks for Green Fuels.” Acs.org, c&cn, 27 Feb. 2022, cen.acs.org/environment/greenhouse-gases/shipping-industry-looks-green-fuels/100/i8.

Madehow. “How Printed Circuit Board Is Made - Material, Manufacture, Making, History, Used, Processing, Parts, Components, Steps.” Madehow.com, 2014, www.madehow.com/Volume-2/Printed-Circuit-Board.html.

Misawa Medical Industry Co., Ltd. “Hypodermic Needle Manufacturing Process.” Www.misawa-Medical.co.jp, www.misawa-medical.co.jp/quality.html.

North American Forest Foundation. “How Much Energy Does It Take to Produce Plastic, Steel, and Wood?” How Much Energy Does It Take to Produce Plastic, Steel, and Wood?, North American Forest Foundation, northamericanforestfoundation.org/energy-costs/.

Nuwer, Rachel. “Oil Sands Mining Uses up Almost as Much Energy as It Produces.” Inside Climate News, 19 Feb. 2013, insideclimatenews.org/news/19022013/oil-sands-mining-tar-sands-alberta-canada-energy-return-on-investment-eroi-natural-gas-in-situ-dilbit-bitumen/.

Stanley Packaging. “Bubble Wrap Manufacturing Process: How Is Bubble Wrap Made? - Stanley Packaging.” Bubble Wrap Manufacturing Process: How Is Bubble Wrap Made?, 20 2015, www.stanleypackaging.com.au/blog/bubble-wrap-manufacturing-process-how-is-bubble-wrap-made/.

The University of Arizona. “Copper Mining and Processing: Processing Copper Ores.” Superfund, 13 July 2020, superfund.arizona.edu/resources/learning-modules-english/copper-mining-and-processing/processing-copper-ores.

U.S. Food And Drug Administration. “Safely Using Sharps (Needles and Syringes) at Home, at Work and on Travel.” FDA, 15 June 2019, www.fda.gov/medical-devices/consumer-products/safely-using-sharps-needles-and-syringes-home-work-and-travel.

United States Department of Transportation. “Table 4-6: Energy Consumption by Mode of Transportation (Trillion Btu) | Bureau of Transportation Statistics.” Www.bts.gov, 22 July 2016, www.bts.gov/archive/publications/national_transportation_statistics/table_04_06.

Waste and Pollution

Kaede Lin
DES40A
16 March 2023

Automated insulin delivery systems, or simply insulin pumps, are devices that allow for people with diabetes to manage their insulin more conveniently and accurately than with manual injections. Like any product, insulin pumps generate waste products throughout their life cycle, primarily during their distribution, usage, and ultimate disposal. Specifically, these waste products include used infusion sets, spent batteries, discarded packaging, and electronic waste for the pump itself. It should be clarified that this is not intended as an argument against the adoption of a life-saving medical technology, but instead as an assessment of its environmental impacts and potential areas for improvement in this regard.

Like most products, the lifecycle of insulin pumps begins with the acquisition of the required raw materials. In this case, the two main categories of materials used in insulin pumps are plastics and metals, both of which also generate waste as byproducts of their extraction/synthesis.

Insulin pumps (and their associated packaging) are made of a variety of different plastics including polyethylene, polypropylene, polystyrene, and polyethylene terephthalate, with the exact composition varying heavily based on manufacturer and model. However, pretty much all synthetic plastics are derived from fossil fuels, mostly crude oil,  (“How Is Plastic Made”). The amount of crude oil consumed is not insignificant either, the production of plastics constitutes eight percent of worldwide crude oil consumption (Knoblauch). The extraction of these fossil fuels however, generates considerable waste. Hydraulic fracking is a common method of extraction and utilizes copious amounts of water and chemical solutes to pulverize rock and free the encased crude oil/natural gas for extraction. After it is used, this contaminated water becomes a waste product and “is frequently disposed of by injection into deep wells, typically into saltwater aquifers. The injection of wastewater can cause earthquakes that may cause damage and are large enough to be felt.” (“Oil and Petroleum Products Explained”). Oil extraction, and by extension plastics production, generates dangerous waste byproducts that cause serious ecological dangers. 

Insulin pumps also require a variety of different metals to manufacture including but not limited to iron, copper, zinc, chromium, lithium, nickel, and silicon (Winkelkötter 899). The exact composition again varies heavily on the make and model. Generally speaking, obtaining metals for manufacturing first involves mining ore from the earth before then refining it into pure metal. The exact details of this process vary significantly and are outside the scope of this paper, but this generalized process holds true for the metals used in insulin pump production. Mining and metal refinement however generate considerable amounts of waste. Whether underground or in open pits, mining involves breaking up rock to expose the ore, creating crushed rock as a waste product. Although the amount of waste rock from underground mines is relatively small, “the amount of waste rock in open pit mines is commonly two to three times the amount of ore produced, tremendous volumes of waste rock are removed from the pits and deposited in areas nearby” (“Metal Mining”). Not only are these massive piles of rock unsightly, “if water infiltrates into pyrite-laden waste rock, the resulting oxidation can acidify the water, enabling it to dissolve metals such as copper, zinc, and silver. This production of acidic water is commonly referred to as “acid rock drainage.”... the resulting acidic and metal-bearing water may drain into and contaminate streams or migrate into the local groundwater”(“Metal Mining”). Additionally, the process of refining and smelting the ore into metal also generates waste, namely in the form of slag (solid smelting byproducts), tailings (unused ore) and gaseous emissions such as sulfur dioxide (“Metal Mining”). Slag and tailings both can release metal particles into the environment similar to how waste rock can, and sulfur dioxide reacts with water vapor to form sulfuric acid, which results in acid rain. In short, the production of metals produces significant waste, most of which cause environmental damage or pose health risks. In the context of insulin pump production however, it should be clarified that their metal usage is miniscule. A single insulin pump uses less than 29 grams (one ounce) of metal in its construction, with some models using significantly less (Winkelkötter 899). 

Once the raw materials are ready, they are transported to factories where they are first made into components that are later assembled into insulin pumps. The plastics are sent to the factory as small pellets where they are melted down and pumped into a solid mold of the desired part (“Injection Molding”). In the case of insulin pumps, this is how parts for the outer shell and reservoir are made, which constitute the bunk of the device. While it is fast, injection molding is not perfect.  Small channels in the mold that allow the plastic to flow from the nozzle to the mold cavities (runners) result in some plastic solidifying outside the part mold and is thus wasted. Fortunately, these runner systems are “the only material waste in injection molding, 15-30% of which can be recycled and reused” (“Injection Molding”). Nevertheless, these plastic scraps are still a waste product that should be managed carefully. 

Meanwhile, the refined metals are turned into the various electrical and mechanical components needed to operate the insulin pump. This includes springs, motors, needles, glucose sensors, and LCDs, but for the sake of simplicity, this paper will only cover one of the most crucial components of the assembly: the printed circuit board (PCB). PCBs typically consist of three main layers: an insulative substrate, a thin conductive copper layer, and finally a protective solder mask (Printed Circuit Board). The manufacturing of these boards is a subtractive process, meaning that material is mostly removed and it thus becomes waste. Specifically, PCB waste comes in the form of board trimmings and drilling shavings, as well as the various chemical solutions used to etch away the copper, all of which are hazardous (Printed Circuit Board). This is a very simplified explanation of the manufacturing process of insulin pumps. The actual process is significantly more complex due to the sheer number of unique components and will vary heavily based on the manufacturer, but these components illustrate the general pattern of waste produced by the manufacturing process.

Once the finished insulin pump is assembled, it is packaged and shipped out to pharmacies and consumers. Needless to say, freight is a significant source of greenhouse gasses, constituting 8% of the worldwide emissions (“Freight Transportation”). This is compounded by the fact that every step and sub-step of a pump’s lifecycle intersects with transportation in some form. The crude oil must be shipped to a refinery to make plastic which also needs to be shipped to a factory for assembly after which it is shipped to the consumer before finally being shipped to a landfill or recycling plant for disposal. Furthermore, the packaging associated with insulin pumps also makes a significant amount of waste. This is mainly due to the fact that many components such as the reservoir and infusion set require replacement every 1-3 days and each of which must have its own sealed packaging to remain sterile. For instance, under ideal conditions, the annual amount of waste generated by a 0.3 kg insulin pump was found to be nearly 6 kilograms (13 pounds), a majority of which comes from the paper and plastic packaging (Winkelkötter 900). That being said, in the context of lost materials, this is not actually all that much waste. “For insulin pump infusion sets with the recommended exchange of infusion sets every 2–3 days (except Cleo), environmental loss of resources is similar to the loss occurring through consumption of one disposable cup of coffee per day and much lower than having one soft drink in an aluminum can per day” (Pfützner 846). Insulin pumps produce a bit of waste, but so does pretty much everything else we do. 

Besides waste due packaging as discussed previously, there are other waste products produced during the usage phase of insulin pumps. Infusion sets, an adhesive pad with an integrated needle and tubing, is one of the more obvious waste products since they must be replaced regularly for hygienic reasons. However, these cannot simply be thrown in the trash as they must be placed in special sharps containers to prevent the possibility of injury (Hoskins). Another waste product is the batteries; the previously mentioned 0.3 kg insulin pump consumes 92 disposable zinc-air batteries per year (Winkelkötter). Disposable pod-based insulin pumps are even worse in this regard, as they have three integrated lithium-ion batteries and thus produce 365 batteries per year (Winkelkötter 899). Batteries in particular are a problematic waste product. Not only do they contain toxic metals that can contaminate nearby environments, “the costs of the recycling processes [for batteries] do not offer economical incentives given that current methods used in recycling batteries to reclaim metals require 6 to 10 times more energy than extracting / refining those metals from ores” (Hamade 416). As such, replacing disposable batteries with rechargeable ones is a possible avenue for reducing waste.  

At the end of their lifespans when the insulin pumps themselves become waste products, specifically electronic waste or ‘e-waste’. “E-waste consists of a large variety of materials … some of which contain a range of toxic substances that can contaminate the environment and threaten human health if not appropriately managed. E-waste disposal methods include landfill and incineration, both of which pose considerable contamination risks” (Kiddee 1238). Even recycling isn’t an ideal solution. Because of how difficult it is to separate the many different materials present in electronic waste, it is frequently shipped to developing countries where environmental and labor protections are weak and sorted by hand with little concern for safety or preventing contamination (Kiddee 1239). There is no real easy or ethical way to dispose of  electronic waste on the scale that it is produced, 

Although it may be easy to see insulin pumps as a wasteful and unsustainable product, these drawbacks are far outweighed by their vital role as a medical technology. Besides, most of the waste associated with the production and assembly of insulin pumps are true of pretty much all electronics to some degree. In short, the waste products entailed by insulin pumps are not due to any flaw in the pumps themselves, but instead inherent to our current system of resource acquisition, manufacturing, and recycling. 

Works Cited

“Freight Transportation.” MIT Climate Portal, https://climate.mit.edu/explainers/freight-transportation. Accessed 16 Mar. 2023.

Hamade, Ramsey, et al. “Life Cycle Analysis of AA Alkaline Batteries.” Procedia Manufacturing, vol. 43, Jan. 2020, pp. 415–22. ResearchGate, https://doi.org/10.1016/j.promfg.2020.02.193.

Hoskins, Mike. “What to Do with Used Diabetes Supplies?” Healthline, 22 Apr. 2021, https://www.healthline.com/diabetesmine/diabetes-supplies-disposal-and-recycling.

“How Can Metal Mining Impact the Environment?” American Geosciences Institute, 13 Nov. 2014, https://www.americangeosciences.org/critical-issues/faq/how-can-metal-mining-impact-environment.

“How Is Plastic Made? Plastic Production Process Simplified.” Plastic Collectors, 17 Aug. 2022, https://www.plasticcollectors.com/blog/how-is-plastic-made/.

“Injection Molding: The Manufacturing & Design Guide.” Hubs, https://www.hubs.com/guides/injection-molding/. Accessed 15 Mar. 2023.

Kiddee, Peeranart, et al. “Electronic Waste Management Approaches: An Overview.” Waste Management, vol. 33, no. 5, May 2013, pp. 1237–50. ScienceDirect, https://doi.org/10.1016/j.wasman.2013.01.006.

Knoblauch, Jessica. “Environmental Toll of Plastics.” Environmental Health News, 1 Feb. 2022, https://www.ehn.org/plastic-environmental-impact-2501923191.html.

“Oil and Petroleum Products Explained - Oil and the Environment.” U.S. Energy Information Administration (EIA), https://www.eia.gov/energyexplained/oil-and-petroleum-products/oil-and-the-environment.php. Accessed 14 Mar. 2023.

Pfützner, Andreas, et al. “Analysis of the Environmental Impact of Insulin Infusion Sets Based on Loss of Resources with Waste.” Journal of Diabetes Science and Technology, vol. 5, no. 4, July 2011, pp. 843–47.

Printed Circuit Board Recycling Methods. Environmental Protection Administration Taiwan, 2012. Zotero, https://www.epa.gov/sites/default/files/2014-05/documents/handout-10-circuitboards.pdf.

Winkelkötter, Jana, and Thore Reitz. “Analysis of the Waste Volume and CO2-Equivalent Caused by the Use of Selected Patch Pumps.” Journal of Diabetes Science and Technology, vol. 16, no. 4, Feb. 2021, pp. 896–903. PubMed Central, https://doi.org/10.1177/1932296821991523.