As veterinarians we use a lot of nitrile gloves. For many years, they just ended up in the landfill where they may take 100 or more years to slowly breakdown into small particles. Fortunately, some exciting options for more sustainable disposal are becoming available.
It is important to note that nitrile gloves cannot be recycled. Simply tossing them into the recycling bin will create more harm than good. When materials are misplaced into recycling units it can interfere with the sorting mechanism and result in blockages that substantially disrupt and slow the process or an entire batch of otherwise appropriate material may be contaminated resulting in diversion of the entire lot to landfill.
The importance of appropriate sorting of waste materials as the veterinary facility level cannot be overstated. Failure to do so can negate or worsen waste disposal impacts.
Grossly contaminated gloves with animal fluids/excrement, infectious or other biohazardous waste, chemotherapeutic drug, or toxic chemicals must undergo appropriate disposal.
Nitrile gloves are made from synthetic materials derived from fossil fuels. Nitrile or more completely – nitrile butadiene rubber (NBR) – is a copolymer derived from two monomers, acrylonitrile and butadiene. Acrylonitrile is produced from a chemical reaction of propene and ammonia. It improves the chemical resistance of the gloves including against non-polar solvents and some gases. Butadiene comes from ethylene and improves the elasticity and tear resistance of the gloves. The free-radical emulsion copolymerization results in the NBR polymer. Polymer coatings are added to the surface of the glove to improve elasticity and a process of chlorination is used to make the surface smoother. Standard nitrile gloves degrade very slowly into smaller pieces over 100-200 years. However, they are far superior to toxic vinyl gloves which will contaminate water and land. A quite comprehensive lifecycle analysis (LCA) of nitrile gloves has been completed by designlife-cycle.com.
At this time the sustainable disposal option for standard nitrile gloves, rather than landfill, is downcycling. This entails collection of the gloves and then sending them off in boxes to facilities that either utilize the material for other plastic products or incorporate them into construction and road materials. This prevents them filling up landfill or worse littering the more general environment. Incineration with adequate capture of pollutants and emissions may be a viable alternative.
Below we will also explore biodegradable nitrile gloves and their emissions.
1. Down-cyclable solutions:
Gamma Carbin program by Polycarbin offers a mail back service for any brand of non-soiled nitrile gloves. The gloves are mechanically shredded and are used as a clean filler material in the cement industry. Bins are sold in packs of 2 or 5. Each bin is 12” x 12” x 26” and holds up to 40lbs. This works well for small and large veterinary facilities. Under Polycarbin’s programs, you can to track and measure your carbon footprint reduction using the Carbin Counter.
RightcycleTM program by Kimberly-Clark Professional® will take back their own made KimtechTM nitrile gloves. Large quantities must be collected into enough boxes to fill an entire pallet and then can be shrink wrapped, labeled, and sent back. Utilizing a recycling plant, these are converted into pellets that can then be made into other products. This will only be practical for very large or centralized facilities.
Zero Waste BoxTM by Terracycle® recycles disposable gloves and face masks. The Zero Waste BoxTMreceptacles come in 3 practical sizes for individual veterinary clinics – small accepts 520 units, medium accepts 1400 units and large accepts up to 2600 units of waste. This works for small and large veterinary facilities. These products are apparently recycled into powder/pellets and then re-manufactured into various products including tiles and rubberized mats due to the elasticity of the material.
2: Biodegradable Nitrile Gloves
In 2012 the first biodegradable nitrile gloves appeared on the market made by Showa, USA, with Eco Best Technology EBTTM. In April 2022, the FDA granted 510(k) medical use approval as a Class I medical device, meeting the ASTM D6319 standard. EBTTM is an organic additive that is inserted into the copolymer during production. These gloves have the same handling, chemical resistance properties, and shelf life as standard nitrile gloves. When the gloves are placed in an active landfill anaerobic setting, microorganisms are attracted to the material, consume the ingredient, and then excrete enzymes that depolymerize the nitrile polymer. 82% is biodegraded in 386 days and within 5 years completely to methane, water, with only a very small amount (<5%) of inorganic non harmful material remaining. This technology has passed stringent short- and long-term US biodegradation standards- ASTM D5511 and D5526, and specifically for EBTTM, attained third party best in industry certification with GreenCircle Certified. Methane is a major by-product in this biodegradation process as with all anaerobic landfill breakdown. Given the GWP100 of methane (28 times the global warming potential of CO2 over 100 years and 80-fold over 20 years) the main concern regarding the sustainability of these biodegradable gloves is their contribution to the emissions of this problematic GHG from landfill waste without methane capture. Unfortunately, methane capture is unavailable for the majority of US and the world’s landfills. In conditions such as in an anaerobic digester or landfills with methane capture capability, methane can be harnessed and burned to create energy. With CO2 capture these facilities can provide zero or low emission electricity.
There are now two veterinary based companies that offer biodegradable FDA-approved medical grade nitrile gloves: natrleÒ from VetFlex and BetterGlovesTM from KVP. These utilize a similar technology as EBTTMknown as BDGTM. BDG drop-in technology increases partial decomposition time to 90% in 490 days by attracting landfill microbes. These gloves also carry the US biodegradation standards – ASTM D5511 and D5526. They also meet the ASTM D6978-05 Resistance to Permeation by Chemotherapy. They are manufactured by Hartalega, in Malaysia, the world’s largest nitrile glove manufacturer. In addition, VetFlex has implemented extensive sustainability initiatives to lower their carbon foot print throughout the entire supply chain including utilizing a distribution warehouse in California powered by 100% solar power and partnering with Polycarbin for standard nitrile glove downcycling through the Gamma Carbin program outlined above.
Other Resources:
- Napa Recycling and Waste Services: https://naparecycling.com/guide/latex-gloves/
- Northeast Recycling Council: https://nerc.org/news-and-updates/blog/nerc-blog/2020/07/21/recycling-options-for-single-use-gloves
- Zhu et al. (2022.) Reusing COVID-19 disposable nitrile gloves to improve the mechanical properties of expansive clay subgrade: An innovative medical waste solution. J Clean Prod. 2022(375);https://doi.org/10.1016/j.jclepro.2022.134086
- Medrux: nitrile glove recycling.
- Medrux: biodegradable nitrile gloves
