Chlorine Dioxide (CD) Contract Sterilization
A low-temperature, non-carcinogenic alternative to ethylene oxide — run in the world's largest contract CD chamber, on the same Colorado campus as our EO and biological testing.
What chlorine dioxide sterilization is
Chlorine dioxide is a true gas sterilant that works at low temperature and low humidity, delivering broad-spectrum sporicidal kill without the carcinogenic residuals associated with ethylene oxide. It has long been used to decontaminate cleanrooms and isolators; at Boulder we run it as a validated terminal sterilization method for medical devices.
We operate the world's largest contract chlorine dioxide chamber — a two-pallet vessel that accepts devices up to roughly eight feet — so CD is available here at a scale the pure-play CD competitors cannot match. And because EO runs in the same building, we recommend CD only when it is genuinely the better fit for your device.
Benefits of chlorine dioxide
Why device makers move part or all of their portfolio to CD.
No carcinogenic residuals of concern
CD does not leave the ethylene oxide and ECH residuals that require lengthy aeration and ISO 10993-7 residual limits.
Low temperature & low humidity
Gentle on electronics, optics, adhesives, and heat- or moisture-sensitive materials — similar material friendliness to EO.
World's largest contract chamber
A two-pallet chamber handles devices up to eight feet — large assemblies most CD providers simply cannot accept.
Broad-spectrum sporicide
Effective against bacteria, viruses, fungi, and resistant spores, validated to ISO 14937 requirements.
Fast cycle, minimal aeration
CD standard cycles run in about five business days with no long EO-style aeration hold to off-gas residuals.
In-house biological testing
BIs/PCDs, sterility, endotoxin, bioburden, and CD residuals tested on site — no inter-vendor shipping.
The green EtO alternative
Ethylene oxide is under growing regulatory and public scrutiny as a hazardous air pollutant, and EO facility closures have repeatedly threatened device supply. Chlorine dioxide gives medical device makers a credible, low-emission path that addresses those pressures head-on:
- No carcinogenic EO residuals to aerate off or document against ISO 10993-7 limits
- Lower environmental and worker-exposure profile, supporting ESG and sustainability commitments
- Reduced dependence on a shrinking pool of EO facilities under regulatory pressure
- A drop-in path for many electronics and combination devices already validated on EO
The honest caveat: EO still penetrates certain long lumens, dense loads, and packaging configurations better than CD. Because we run both, we will tell you when EO remains the right call rather than push you to the method we are selling. See the EO option or how we choose between them.
Our chlorine dioxide history
Boulder did not start as a chlorine dioxide company — and that matters. We were medical device designers first, ran ethylene oxide as our original sterilization method, and added chlorine dioxide as the technology matured, ultimately building the largest contract CD chamber in operation.
That sequence is the whole point. We evaluate CD against EO from real operating experience with both methods and from the device developer's chair — not as a single-method shop defending the only tool it owns. When a CD-only competitor says they “created the market,” our answer is simpler: we have run both methods across hundreds of products and dozens of validations a year, so we can recommend the one your device actually needs.
Chlorine Dioxide FAQ
What is chlorine dioxide sterilization?
Chlorine dioxide (CD) is a true gas sterilant that works at low temperature and low humidity. It is a broad-spectrum sporicide effective against bacteria, viruses, fungi, and spores, validated for medical devices as an alternative to ethylene oxide.
How is chlorine dioxide different from ethylene oxide?
Chlorine dioxide has no carcinogenic residuals of concern, requires no long aeration to off-gas EO, and is not subject to the same emissions scrutiny as ethylene oxide. It is a strong green alternative for electronics, combination devices, and sustainability-driven programs — though EO still penetrates certain geometries and packaging better, which is why we offer both.
What size devices can your CD chamber handle?
We operate the world's largest contract chlorine dioxide chamber — a two-pallet chamber that accommodates devices up to roughly eight feet. That scale lets us handle large or awkward assemblies the pure-play CD shops cannot.
Is chlorine dioxide validated for medical devices?
Yes. Our CD process is run under an ISO 13485 quality system and aligned to ISO 14937 (the general requirements standard for a sterilizing agent), with overkill or bioburden-based release scoped to your device.
Why switch from EtO to chlorine dioxide?
Common drivers are eliminating carcinogenic EO residuals, avoiding lengthy aeration, reducing emissions exposure, and meeting sustainability or ESG commitments. Because we run both methods, switching is low-risk — we can keep your EO process as a fallback while qualifying CD.
How long has Boulder run chlorine dioxide?
Boulder operated ethylene oxide first and added chlorine dioxide as the technology matured, building the largest contract CD chamber in the process. That history means we evaluate CD against EO from real operating experience with both — not as a single-method vendor defending its only tool.
Considering chlorine dioxide for your device?
Tell us about your device and current method. We will scope a CD cycle — and tell you honestly if EO is the better fit — within one business day.