Medical waste is generated from healthcare facilities and contains potentially harmful microorganisms that can infect hospital patients, health workers and the general public.

——World Health Organization (WHO)

Type of Medical Waste

Infectious Waste: waste known or suspected to contain pathogens and pose a risk of disease transmission, e.g. waste and waste water contaminated with blood and other body fluids, including highly infectious waste such as laboratory cultures and microbiological stocks; and waste including excreta and other materials that have been in contact with patients infected with highly infectious diseases in isolation wards.

Sharps: used or unused sharps, e.g. hypodermic, intravenous or other needles; auto-disable syringes; syringes with attached needles; infusion sets; scalpels; pipettes; knives; blades; broken glass;Pathological Waste: human tissues, organs or fluids, body parts, foetuses, unused blood products and contaminated animal carcasses;

Chemical Waste: Solvents and reagents, disinfectants, sterilant, etc.

Pharmaceutical Waste: pharmaceuticals that are expired or no longer needed; items contaminated by, or containing, pharmaceuticals. Cytotoxic waste containing substances with genotoxic properties, e.g. waste containing cytostatic drugs (often used in cancer therapy); genotoxic chemicals

Hazards of Medical Waste

• Infection Risks

Pathogen Transmission：Improper handling can lead to needlestick injuries or direct contact, posing severe health risks to healthcare workers, waste handlers, and the public.

Epidemic Spread：During outbreaks (e.g., COVID-19, Ebola), mismanaged medical waste can amplify disease transmission in communities.

• Environmental Pollution

Soil and Water Contamination：Chemicals and pharmaceuticals leaching into soil/groundwater disrupt ecosystems and enter the food chain.

Air PollutionOpen burning or inefficient incineration releases toxic fumes (e.g., dioxins, furans) linked to cancer, respiratory diseases, and climate change.

• Public Health Crises

Communities near poorly managed waste sites face higher rates of infections, chronic diseases, and reduced quality of life.

WHO Statistics

According to WHO/UNICEF, in 2021, only 61% of hospitals had basic health-care waste services. The situation is far worse in fragile contexts, where based on 2023 data, only 25% of health facilities had basic health care waste management services.

Proper management of medical waste is fundamental to safeguarding both public health and the environment. While incineration has been employed for decades as a primary method of disposal worldwide, it also carries serious risks. When not properly designed or operated, medical waste incineration is a main source to generate invisible but extremely dangerous byproducts — most notably dioxins and furans, among the most toxic compounds known.

What is Dioxin

“Dioxins” are a group of chemically related compounds:

• Polychlorinated dibenzo-p-dioxins (PCDDs) and
• Polychlorinated dibenzofurans (PCDFs).

classified as persistent organic pollutants (POPs) that unintentionally produced during the incineration of waste containing chlorine
(e.g. PVC plastics). They are colorless, odorless, and highly toxic even at trace levels.

• Highly toxic:Known to cause cancer, reproductive and developmental problems, and damage to the immune system
• Persistent:Remain in the environment for years.
• Bioaccumulative:Build up in the food chain, especially in animal fats.

Even small amounts of dioxin exposure can have significant health impacts. The World Health Organization has listed dioxins among the most dangerous environmental contaminants.

How is Dioxin Formed

Dioxins are unintended byproducts formed during combustion processes involving chlorine, oxygen at a temperature range. The formation in medical waste incinerators is a complex chemical process, but it can be broken down into three key requirements:

1. The Necessary Requirements

For dioxins to form, three basic elements must be present:

• Chlorine:from PVC, chlorinated disinfectants, saline residues, etc. No chlorine, essentially no dioxin formation.
• Oxygen:Readily available from the air used for combustion.
• Temperature window:dioxins are dramatically formed within the temperature range 300-500C. In the hot furnace (typically above 850°C, chlorine and carbon compounds break apart. However, during cool down, they pass through this critical temperature range. This is where the most significant dioxin formation occurs.

Source: Relative formation rates of dioxins (relative to 400°C case) at different flue gas temperature (McKay, 2001).

Why Medical Waste Incineration Generates Dioxin?

Medical waste often meets an abundance of all these requirements to generate dioxin:

• a significant proportion of plastics, disinfectants, and chemical residues.
• Oxygen presence.
• In incinerators that do not reach and maintain the necessary high temperatures (850–1100 °C) or lack adequate flue-gas cleaning systems, combustion is incomplete. This creates a perfect scenario for dioxin generation.

Once emitted, dioxins disperse into the air, settle on soil and vegetation, and eventually enter the food chain. Unlike many pollutants, they do not degrade easily, making even small releases a long-term environmental and public health concern. 

Different types of incineration used

1. Open Burning

• Conducted in pits or rudimentary chambers without emission control.
• Burning uncomplete and in limited temperature, producinglarge amounts of smoke, toxic particles, and extremely high levels of dioxins.
• Still practiced in under-resourced regions, but considered the most hazardous and outdated method.

2. Small Incinerators

• Used by small hospitals or rural clinics.
• Often operate at insufficient and unstable temperatures.
• Limited or no gas treatment systems.
• Appear controlled but can be dangerous sources of dioxin emissions if not engineered to international standards.

3. Large-Scale Incinerators

– Rotary kiln, gasifier (called pyrolysis incinerators sometime)

• Properly designed Industrial facilities with advanced and complex flue-gas treatment processing high volumes of medical waste can reduce risks significantly.
• The necessarity to have strict operational control and facilities are well maintained by a professional operation team.
• High operation and maintenance cost to meet international emission standards.
• Even though, large-scale systems emit harmful levels of pollutants and leave toxic ash.

Dioxin Emission from Medical Waste Incineration

WHO / UNEP Guidelines on Best Available Techniques and Best Environmental Practices (2006) → recommend the same 0.1 ng TEQ/Nm³ limit for medical and hazardous waste incineration.

Source: Findings on an Assessment of Small-scale Incinerators for Health-care Waste – WHO 

The Alternative: Non-Incineration Treatment Technologies

Given the severe health and environmental risks associated with incineration, many countries have shifted toward cleaner, more sustainable methods of managing medical waste. These technologies neutralize pathogens without generating dioxins or other hazardous air pollutants, making them safer both for communities and the environment.

Autoclaving (Steam Sterilization)

• Usinghigh-temperature, pressurized steam to sterilize medical waste, effectively eliminate all microorganisms, including resistant pathogens.
• Generates no dioxins or furans, making it a much safer alternative.
• Produces negligible emissions and is highly cost-efficient compared toState-of-the-Art incineration technologies.
• The safest proven sterilization method over decades in human history.

The U.S. Case: From 6,000 Incinerators to Autoclaves
In the 1990s, the United States operated approximately 6,000 medical waste incinerators. However, the implementation of the Clean Air Act Amendments of 1990 and the subsequent 1997 EPA regulations on hospital/medical/infectious waste incinerators (HMIWIs) drastically changed this landscape. Once stringent dioxin emission limits and monitoring requirements were enforced, many incinerators were shut down or replaced with safer treatment methods. After years of technology evaluation, high-vacuum autoclaving emerged as the dominant solution. Today, over 90% of medical waste in the U.S. is treated by autoclaving.

Other Non-Burn Alternatives

Microwave disinfection: Uses microwave energy to heat and disinfect waste. The production cost is relatively low, and it is mostly used in small equipment with low disinfection requirements, and is rarely used in centralized treatment plants or big capacity projects.

Chemical disinfection: Employs chemical agents (e.g., chlorine compounds) to inactivate pathogens. The cost is very low, but due to the problem of secondary pollution, it is rarely used now..

Thermal treatment (non-incineration): High-temperature methods such as friction heat, very limited application with low capacity and low disinfection requirements.

A Safer Way Forward

At Gient, we are committed to providing safe, environmentally responsible medical waste treatment solutions that eliminate the dangers of dioxins and other toxic emissions.

Contact us now for your medical waste solutions.

Medical waste treatment technologies are mainly divided into incineration and non-incineration methods. Incineration was once the dominant choice worldwide because it can rapidly destroy pathogens and reduce waste volume. However, it also produces hazardous emissions—especially dioxins, furans, and heavy metals—that pose serious risks to human health and the environment.

Curious about incineration and its challenges?

In contrast, non-incineration technologies have emerged as safer and more sustainable alternatives. Some, such as autoclave (steam sterilization), are now widely adopted and recognized as reliable, low-emission mainstream solutions. Others—such as microwave disinfection, chemical disinfection, dry heat systems, and plasma arc technologies—offer varying levels of maturity and application, each with its own advantages and limitations.

Driven by stricter environmental regulations and growing awareness of pollution risks, many countries are transitioning from traditional incineration to a more diversified mix of treatment methods, with non-burn solutions increasingly favored as the future of medical waste management.

A Brief History: Regulation as a Catalyst

The history of medical waste treatment was revolutionized by environmental regulation. For decades, incineration was the dominant, largely unregulated method. A major turning point was the U.S. Clean Air Act of 1990, which established stringent emission standards for medical waste incinerators in 1997. This dramatically increased the cost and complexity of compliant incineration. At that time, there were more than 6,000 medical waste incinerators operating nationwide. Within just a few years, the vast majority were shut down because they could not comply with the new limits.

This regulatory shift directly catalyzed the development and commercialization of alternative non-burn technologies. In the years following the Clean Air Act, technologies like autoclaving (steam sterilization), microwave disinfection, chemical disinfection, plasma arc, ozone treatment, and dry heat became available and adopted, creating a safer, more diverse, and environmentally conscious industry. Today, over 90% of U.S. medical waste is treated by autoclaves, proving that cleaner alternatives are both practical and effective.

Common Alternative Technologies & Their Application Status

Why Alternatives Matter

Health & Safety: No dioxins, furans, or toxic emissions.

Environmental Protection: Lower pollution, reduced contamination risk.

Cost-effectiveness: Lower long-term operational and maintenance costs.

Regulatory Compliance: Meets stringent modern emission standards.

Find a Medical Waste Treatment Solution

The future of medical waste management lies in sustainable technologies. At Gient, we are committed to advancing these technologies, ensuring that medical waste treatment safeguards people and the planet.

Medical waste is dangerous because it often contains infectious materials such as blood, sharps, and contaminated plastics. To make this waste safe, it must be either sterilized or disinfected. While the two terms are sometimes used interchangeably, they are very different in practice — and the difference directly affects safety, sustainability, and recycling.

What is Sterilization?

Definition: Sterilization eliminates all forms of life — bacteria, viruses, fungi, and even highly resistant spores.

Assurance level: Validated to a Sterility Assurance Level (SAL) of 10⁻⁶, meaning less than one chance in a million that a single microorganism survives.

But SAL 10⁻⁶ is not the full story. The type of test spore used to validate the process matters:

When sterilization is proven against the most resistant spores for that method, safety is guaranteed. Autoclaves (steam sterilization) validated with G. stearothermophilus spores provide the highest assurance of sterilization for medical waste.

What is Disinfection?

Definition: Disinfection reduces microorganisms but does not necessarily kill them all.

Limitations: Spores and some pathogens may survive.

Use: Suitable for surface cleaning or liquid waste. A minimum recommended requirement for general medical waste treatment.

International Criteria of Medical Waste Treatment

The STAATT criteria (State and Territorial Association on Alternative Treatment Technologies) define microbial inactivation levels:

Level I Inactivation of vegetative bacteria, fungi, and lipophilic viruses at a 6 Log10 reduction or greater

Level II Inactivation of vegetative bacteria, fungi, lipophilic/hydrophilic viruses, parasites, and mycobacteria at a 6 Log10 reduction or greater

Level III Inactivation of vegetative bacteria, fungi, lipophilic/hydrophilic viruses, parasites, and mycobacteria at a 6 Log10 reduction or greater; and inactivation of B. stearothermophilus spores (Geobacillus stearothermophilus spores) and B. subtilis spores (Bacillus atrophaeus spores) at a 4 Log10 reduction or greater

Level IV Inactivation of vegetative bacteria, fungi, lipophilic/hydrophilic viruses, parasites, and mycobacteria, and B. stearothermophilus spores (Geobacillus stearothermophilus spores) at a 6 Log10 reduction or greater

Level III disinfection has been the recommended minimum criteria by STAATT.

STAATT Levels Achieved by Common Technologies

 Only autoclaves are the common used technologies to reliable achieve STAATT Level IV sterilization and SAL-6 (6log10), validated with G. stearothermophilus spores. 

Why Microwave is Not Sterilization

Microwave systems are sometimes misunderstood as “sterilization,” but in reality they are disinfection technologies.

How microwaves work

Microwaves usually do not directly kill germs. Instead, they mainly heat the moisture inside the waste (or extra moisture injected into the system). The hot environment can kill many bacteria and viruses, but it is not the same as the temperature controlled in pressurized steam sterilization.

Not the right spores for validation

Microwave systems use Bacillus atrophaeus spores for testing, however, these are used for dry heat. In a moist processing environment. 6log10 (99.9999%) of Bacillus atrophaeus spores does not validate SAL 10⁻⁶ of sterilization assurance. That means microwaves cannot scientifically prove sterilization at the required.

Industry recognition

In the medical industry worldwide, microwave systems are not validated or accepted as a sterilization technology.

Why Autoclave Sterilization is Safer

Proven by the toughest spores (G. stearothermophilus), not just easy-to-kill organisms.

Complete safety: eliminates all pathogens, including HIV, hepatitis, TB, and COVID-19.

No toxic emissions: unlike incineration.

Cost-effective: cost-effective in operation and maintenance.

Enables recycling: sterilized plastics and other materials can be safely recycled.

Globally compliant: meets WHO, EU, and EPA standards.

Advanced: The modern medical waste autoclave system efficiently solve most of the problems in medical waste world.

At Gient, our first priority is protecting people and the planet. We are dedicated to the highest standards of safety and sustainability in every solution we deliver.