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Blue-Zone Technologies’ Anesthetics Collection Systems

Each Deltasorb® or Centralsorb® canister contains Blue-Zone’s proprietary adsorbent, Deltazite®, for the capture and removal of all commonly used halogenated anesthetic gases, sevoflurane, desflurane and isoflurane, from the scavenged gas.  The adsorbent is a unique high-silica based filtering matrix, beads or pellets, with a precise pore lattice structure and is housed in custom designed Deltasorb® or Centralsorb® Collection Canister.

The system captures 100% of available scavenged anesthetic gas.  The amount held per canister varies, based on the size of the canister.  Adsorbent capacity is proprietary information that Blue-Zone factors in when sizing the canisters and setting the change-out frequency for each hospital site. That said, Deltasorb® canisters can adsorb approximately two bottles of halogenated anesthetics.

As a general rule, Canisters should be handled consistent with the normal safety precautions that staff use for handling equipment used in the operating room or mechanical room. The Canister should have the inlet and outlet connection sealed with end-cap at each side during transport and when not in use. The Deltasorb® and Centralsorb® Canisters remain Blue-Zone’s property at any point of time and are not to be open, tempered or tested.

Blue-Zone will conduct an initial hospital site technical audit and decide which solution is better suited based on hospital-specific conditions, such as total number of ORs, existence of dedicated AGSS, space allowance, active or passive scavenging, type of AGM deployed, etc. Deltasorb® is preferred over Centralsorb® for its portability in settings that allow conducting general anesthesia in rooms not connected to hospital’s scavenging system, such as ICUs. Centralsorb® is preferred in institutions where the ORs are connected to the hospitals scavenging system.

No. The Deltazite® adsorbent is released to specification which includes a minimum crush strength to ensure the adsorbent maintains its integrity throughout its life cycle. The Canister internals are engineered to retain the adsorbent inside the canister during normal movement, vibrations or rattling.

Blue-Zone Technologies’ Recovery and Production Process

The recovery process is the controlled removal and liquefaction of the captured anesthetics from the proprietary Deltazite® adsorbent into a halogenated condensate released as anesthetic raw material.  The regenerated Deltazite® can then be used again to capture more halogenated anesthetics.

The finished drug production is a controlled proprietary molecule-specific distillation process used to isolate each anesthetic component (Desflurane, Sevoflurane and Isoflurane) from halogenated condensate (the output from the recovery process) into the USP grade generic anesthetic.

Deltasorb® or Centralsorb® systems capture 100% of available scavenged anesthetic gas that passes through the canister and turns virtually all of the captured desflurane is processed into Blue-Zone’s approved generic Desflurane USP.

Blue-Zone’s submission for approval of its generic Sevoflurane USP is currently under review by Health Canada, pending approval expected by year-end 2022. Meanwhile, the recovered and processed finished product Sevoflurane, USP is used for mandatory regulatory studies to support the DIN application while stockpiling the remainder.  Blue-Zone is also stockpilint all processed finished product Isoflurane USP.

Collection Service Benefits

  • Safe capture of waste anesthetic emissions for recovery and production of generic anesthetics
  • Immediate and Measurable GHG/Carbon Footprint Reduction
  • Health co-benefits; daily air quality improvement for hospital’s surrounding community
  • Accreditation Benefits – Greening Leadership & Excellence
  • Centralsorb® installation eligible for a LEED® point.
  • Passive installation with no moving parts – Easy maintenance and simple to exchange
  • Cradle to Cradle® stewardship and responsible management of anesthetic administration
  • Enabled savings on future anesthetic expenditures
  • Enabled alternate and sustainable supply source of medically essential drugs
  • Supply Security in case of foreign supply disruption

Blue-Zone provides Quarterly reports indicating the tonnes of CO2 equivalent of emissions prevented from going into the environment and nearby community. These reports are used for Blue-Zone Certification purposes, future carbon offsets and tracking Hospital’s contribution to Blue-Zone’s anesthetic raw material pool.  The Centralsorb® installation is recognized as climate change mitigation strategy, eligible for LEED® Points (Leadership in Energy and Environmental Design).


The cost is nominal, typically a monthly fee per Operating Room.  Included in a Blue-Zone subscription are the following:

  • Auxiliary equipment supply – mounting bracket, connecting adapters, hoses, etc. as needed
  • Used/Fresh Canisters Cart Exchange at the Hospital’s site
  • A hospital-specific quarterly performance greenhouse gas savings report
  • Ongoing performance support and continued staff training as required
  • Technical Audit of Hospital’s Site and Observation Report
  • First On-site staff training and In-Service
  • Refundable Deposit on the Deltasorb® and/or Centralsorb® canisters.

General questions – Waste Anesthetic Gases

During clinical use, only less than 5 % of inhalation anesthetic used for surgeries general anesthesia is metabolized by the patient. Subject to minor losses in the recovery room and undesired incidental leaks in the Operating Room, a vast majority of the remaining 95% is expelled unabated into the nearby environment via the hospital’s ventilation system. These gases are recognized as health and occupational hazard in the operating room and, when released into the atmosphere, become aggressive GHGs, harmful to the environment and public health.

Their Global Warming Potentials relative to GWP for CO2 of 1, are indicated in the table below.

Global Warming Potential Values for Inhalation Anesthetics
Source: IPCC* Sulbaek** Ozelsel***
GWP20-year* GWP20-year** GWP1-year***
Desflurane 5,550 6,810 8,600
Sevoflurane 795 440 4,300
Isoflurane 1,800 1,800 6,700

* IPCC, Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, pp 734-735.

** M. P. Sulbaek Andersen, “Assessing the Impact on Global Climate from General Anesthetic Gases,” Anesthesia and Analgesia, vol. 114, no. 5, pp. 1081-1085, 2012

***Timur J-P Ozelsel Can J Anesth, https://doi.org/10.1007/s12630-019-01385-w


Global Warming Potential Values for Inhalation Anesthetics
Source: IPCC* Sulbaek**
GWP20-year GWP100-year GWP20-year GWP100-year
Desflurane 5,550 1,790 6,810 2,540
Sevoflurane 795 216 440 130
Isoflurane 1,800 491 1,800 510

* IPCC, Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, pp 734-735.

** M. P. Sulbaek Andersen, “Assessing the Impact on Global Climate from General Anesthetic Gases,” Anesthesia and Analgesia, vol. 114, no. 5, pp. 1081-1085, 2012


In 2019 Greenhouse Gas (GHG) emissions in the USA were estimated to be 4.7 Giga Tons of CO2.*. Blue-Zone estimates that approximately 5.0 Mega Tons of CO2 equivalents from waste anesthetics are emitted each year in the USA^.  It is important to note that the daily emissions of GHG from medically essential volatile anesthetics is “never ending” with cumulative impact.  This impact is mainly focused in urban areas surrounding hospitals with surgical suites.  It is also important to note that surgery volumes are increasing due to more frequent and more complex surgeries conducted to support aging and overall population growth.

The use of Blue-Zone’s Anesthetic Collection Service captures 100% of available anesthetics prior to its release into the community, contributes to environmental protection and provides health co-benefits for the near-by community due to exposure to waste anesthetic gases.

*2021 Union of Concerned Scientists Data: IEA Atlas of Engery

^Calculations available upon request

Blue-Zone currently provides its Anesthetic Collection Service to hospital subscribers in North America. Our hospital subscribers may gain Blue-Zone’s Certified  Eco-Hospital status and become part of a growing global network. Europe is our next target market.

Hospital’s environmental footprint of venting 1 L of anesthetic to the atmosphere is 5.44 tonnes eCO2a.  (Assuming 50% desflurane and 50% sevoflurane). Note: 1 L of anesthetic is approx. 4 bottles)

Blue-Zone’s environmental footprint of capturing/processing/transportation is approximately 0.024 tonnes of eCO2b,c.  (Assuming ground transportation, distance of 4,300 km)

Therefore, Blue-Zone’s Service has a negligible environmental footprint.

  1. a) IPCC, Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, pp 734-735
  2. b) Processing of 1 L of anesthetic: ~ 27 KWH of electricity; equivalent to 0.019 tonnes eCO2 according to EPA) (https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator indicates 0.0007 tonnes eCO2 per KWH).
  3. c) Transportation of 1 L captured on Deltasorb® canisters will vary based on mode of transportation and the distance from Blue-Zone’s facility. Ground transportation accounts for highest CO2 emissions and worst-case example shipping from Toronto, ON to Victoria, BC (4,372 km) would generate 0.005 tonnes eCO2 (Source: https://timeforchange.org/co2-emissions-shipping-goods).

Healthcare workers in a variety of settings can be exposed to the anesthetic gasses that are released or leak out during medical procedures. These gases and vapours are known as waste anesthetic gasses (WAGs).

People who work in hospitals in areas such as operating, labour and delivery rooms, recovery rooms, and in remote anesthetic locations such as radiology or post anesthetic care unit, as well as those who work in dental offices and veterinary clinics and animal research facilities may be exposed to waste anesthetic gasses.

The WAGs and vapors of concern are nitrous oxide and halogenated agents (vapors) such as halothane, enflurane, isoflurane, and desflurane.

NIOSH (the National Institute for Occupational Safety and Health) (2007) states that “exposure to high concentrations of waste anesthetic gases – even for a short time – may cause the following health effects:

  • Headache
  • Irritability
  • Fatigue
  • Nausea
  • Drowsiness
  • Difficulties with judgment and coordination
  • Liver and kidney disease”

NIOSH (2007) continues: “Although some studies report no adverse health effects from long-term exposure to low concentrations of waste anesthetic gases, several studies have linked such exposure to miscarriages, genetic damage, and cancer among operating-room workers. Studies have also reported miscarriages in the spouses of exposed workers and birth defects in their offspring.”

NIOSH (2015) later reports that “Some studies have documented adverse health effects (e.g., headaches, fatigue, irritability, birth defects, miscarriages, liver and kidney disease, cancer) from excessive exposure to anesthetic gases. These health effects were mainly noted for older anesthetics (e.g., trichloroethylene, methoxyflurane) that are no longer commonly in use. … Studies are inconclusive on the potential health effects from occupational exposure to some of the newer anesthetics, such as isoflurane.”

How it works at hospitals?

Deltazite® acts as a lobster trap.  Its uniform, specifically sized pore openings and its organophilic properties make it a highly selective adsorbent for halogenated ethers, such as desflurane, sevoflurane and isoflurane.  As the scavenged gas passes through Deltazite® matrix, housed within the Deltasorb® or Centralsorb® canister, the halogenated anesthetic molecules are adsorbed within the adsorbent pores and adhere to its internal surface within the cavity of the pores through Van der Waals’ forces and electrostatic forces with minimal co-adsorption of moisture related to site-specific factors.  Molecules that are larger than the pore openings are not adsorbed into the pore lattice structure, remain in the scavenged gas and go straight through the Canister.

The adsorption process is exothermic, and a small negligible amount of heat is released. The canister geometry is engineered to withhold the temperature differential without adverse impact on the mass transfer during adsorption.

Deltasorb® and Centralsorb® Canisters loaded with a proprietary Deltazite® matrix can capture all three commonly used anesthetic agents in parallel: desflurane, sevoflurane and isoflurane.

No. The anesthetic gases are trapped within the cavities of the lattice structure of the adsorbent with no degassing until subjected to specific process conditions at Blue-Zone’s production facility. The end-caps on the inlet/outlet of the canister are to be placed when canister is not in use to prevent entry of the particulate matter or other exterior contaminants into the canister during storage or transport.

We remove halogenated anesthetics from the hospital’s scavenged gas by adsorption on Blue-Zone’s proprietary Deltazite® adsorbent. The absorbent is housed in our Deltasorb® and Centralsorb® canisters.

Instructions for use

Deltasorb® canisters have a metal housing that may be slightly magnetic. However, they can be used for MRI setting with no risk if placed just outside the room with hose attached to the AGM. Deltasorb® canisters allow any room not connected to the AGSS system to be safely used for general anesthesia.

The hospital has the authority to decide who is responsible for canister handling and change-outs, based on the site-specific established frequency, typically 1-2 times per week for Deltasorb® or 2-3 times per month for Centralsorb®.  Both jobs are simple enough to be performed by virtually any department and can be completed in a matter of minutes.

No.  Both Deltasorb® or Centralsorb® are passive systems for easy maintenance with no pumps and no moving parts. Blue-Zone provides adapters to fit Hospital’s existing connections, as necessary.  A minor hospital specific retrofit for Centralsorb® system at the AGSS source equipment connection, downstream of the vacuum pumps, includes providing two T’s and a 3-by-pass valve, now also incorporated in the upcoming new edition of the CSA standard Z7396.1 for Medical Gas pipeline system, including inhalation anesthetics, to allow for future implementation of Anaesthetic Capture/Recycling equipment in a newly built hospital.

Labels and Identifications

Blue-Zone follows Health Canada’s requirements for Canister tracking and tracing as part of our quality control systems. We use the serial number as a means to identify the source of recovered halogenated condensate, and to track the location of each canister in the healthcare system.

We recommend that Hospitals remove labels from used Deltasorb® canisters during the change-out, to clearly distinguish between used and fresh. Regardless of whether the labels have been removed, Blue-Zone monitors Hospital’s capture performance from each canister during controlled processing at its facility and recommends revisions to the change-out frequency if and as required.

Logistics & Safety

No. The captured material is safely contained/trapped within the lattice structure of the adsorbent and there is no degassing.  The canister is simply a non-pressurized filter. The metal canister housing, the Deltazite® adsorbent inside, and the anesthetics captured within the adsorbent are all considered nonhazardous and are not dangerous materials. They are safe to handle and transport via standard couriers, by ground, or air. Supporting MSDS available for each.

No.  The canister system is non-pressurized with no risk of explosion.  Exterior is made of metal. The adsorbent inside the canister is an inert high-silica based material and the adsorbed anesthetics are also non-flammable compounds.

Full canisters are returned to Blue-Zone’s production facility, subject to Health Canada’s compliant inspection and logged-in to a canister management database using canister-specific serial numbers. This ensures location tracking and performance tracing of each individual canister. Next, the captured anesthetic is recovered from Deltazite® adsorbent into liquified anesthetic raw material, halogenated condensate, and further processed into individual generic anesthetics using Blue-Zone’s globally patented technologies.

The regenerated canisters are ready for continued use and re-circulation with hospitals.

Regulatory approvals

The company is currently scaling up its production capacity for commercial sale of its Health Canada Approved Desflurane and plans to commence in early 2023.  This will coincide with the expected Health Canada approval for Blue-Zone’s Sevoflurane, USP.  Blue-Zone is currently exploring regulatory approvals in the USA and European Union.

Desflurane, with its highest Global Warming Potential (GWP) Index among the three commonly used anesthetics, is the most polluting anesthetic and was Blue-Zone’s first application submitted with Health Canada to allow its use without harming the environment, in tandem with capturing 100% of scavenged drug prior to its release into the community. Blue-Zone’s production line can produce Desflurane USP, Sevoflurane USP and Isoflurane USP using the same equipment with adjusted molecule-specific control parameters.

The Sevoflurane USP submission was recently filed and is currently under Health Canada’s review with pending approval expected by year-end 2022.

Isoflurane USP submission is under consideration based on market demand.

When to exchange

Canisters are engineered as standalone devices.  Blue-Zone uses its proprietary information for sizing the canister to withhold the adsorbed amount of halogenated anesthetic expected for a pre-determined length of time in use, customized for hospital practices and equipment.  The site-specific change-out schedule is set, based on surveyed hospital conditions, anesthetic usage, and canister sizing.

Once the Deltazite® adsorbent reaches capacity and is saturated, it will no longer adsorb halogenated anesthetic molecules from the scavenged gas and the gas flow through the canister will be of the same anesthetic concentration at the inlet and outlet. Hence, for the purpose of continuous capture without losses of halogenated anesthetics, it is critical to monitor and adhere to Blue-Zone’s recommended change-out frequency schedule.

Blue-Zone works with each hospital site to develop the change schedule to optimize the quantity of anesthetic captured based on the capacity of the adsorbent.  This is covered during the initial training and the In-Service session.  The site-specific change-out schedule is set and followed. Blue-Zone monitors the amounts captured from each canister during controlled processing at its facility and recommends revisions to the hospital change-out frequency if and as required.