Ecofox's Scientific Interpretation of the Carcinogenicity of Glass Fiber - Part 2

Part 4

Introduction: The History and Scientific Revision of the "Carcinogenic" Label

1. Consensus of international health organizations

The IARC's revised conclusions have been widely accepted: the U.S. National Toxicology Program (NTP) has explicitly removed the carcinogenic warning label for biosoluble glass wool in its subsequent carcinogen reports; health agencies in the EU, Canada, and other regions have also updated their assessments, confirming that glass wool used for insulation in daily contact does not pose a significant carcinogenic risk.

2. EUCEB certification: A "non-carcinogenic passport" for European mineral wool products.

EUCEB (European Committee for Certification of Mineral Wool Products), as the authoritative certification body in the European mineral wool industry, independently verifies the safety of products such as glass wool and rock wool through rigorous biosolubility testing. Its certification standards require products to meet the following requirements:

• Fiber decomposition rate: The product must be rapidly dissolved by lung fluid after entering the human body, preventing long-term accumulation;

• Non-carcinogenicity verification: Animal inhalation experiments and occupational exposure data demonstrate that the product poses no risk of chronic damage.

Products certified by EUCEB can use the "non-carcinogenic substance label," indicating that they meet the strictest health and safety standards in the European Union. This label is currently used by mainstream insulation material manufacturers in more than 30 countries.

3. Fraunhofer Institute for Materials Safety Assessment

The Fraunhofer Institute in Germany, a leading global institution for applied scientific research, has further corroborated the safety of glass wool through its research in the toxicology of fiber materials. Its 2019 report, "Biosafety Report of Building Insulation Materials," states:

• Glass wool products conforming to EN 13162 standards (such as insulation fibers with a diameter > 5 μm) cannot enter the lungs through the respiratory tract, resulting in actual exposure doses far below the carcinogenic threshold;

• Biosoluble glass wool exhibits a dissolution rate exceeding 90% within 48 hours in simulated lung fluid, and will not cause chronic damage.

This conclusion is highly consistent with IARC's "3D principle" (dosage, size, durability), providing authoritative engineering practice support for the safe application of glass wool.

Part 5

Selective blindness in the public sphere: the disconnect between scientific conclusions and information dissemination

1. Persistent dissemination of old conclusions and causal analysis

Despite the IARC's revision over 20 years ago, the old conclusion that "glass fiber is a Group 2B carcinogen" continues to circulate widely on the Chinese internet. The core reasons include:

• Information lag and fragmented dissemination: The public lacks follow-up on updated scientific conclusions. Early labels, due to the keyword "carcinogenic," easily attract attention, while the revision process is marginalized due to its highly specialized nature and high barrier to dissemination.

• Deliberate misleading driven by traffic: Some marketing accounts and non-professional media, in pursuit of clicks, selectively extract old conclusions from 1988, creating panic with headlines like "Shocking!" and "Carcinogenic Warning," ignoring the timeliness of scientific evidence.

2. The Responsibility of Science Communication and Cognitive Correction

The value of scientific conclusions lies in their dynamic updating, and information disseminators must bear the responsibility of "presenting scientific progress in a timely and complete manner." Treating preliminary conclusions from 30 years ago as "the latest discoveries" essentially ignores the scientific method ("hypothesis-verification-revision") and misleads the public in making rational choices about practical products such as building insulation materials and industrial fibers.

Part 6

Core principles of toxicology: The "3D principle" explains the safety of glass fiber

Modern fiber toxicology has reached a consensus: the pathogenicity of a fiber does not depend on its "name", but on three core characteristics: dose, dimension, and durability ("3D principle").

1. Dose: Discontinuation dose toxicity assessment is not meaningful

"Dosage determines toxicity" is a fundamental principle of toxicology. In everyday exposure, the exposure dose to glass wool fibers is extremely low: in home decoration settings, fiber release is far below the occupational exposure limit (PEL); even for factory workers with long-term exposure, epidemiological studies have not found an increased risk of cancer (IARC Vol. 81). The amount of fiber inhaled by the general public through respiration is even less than sufficient to reach the "carcinogenic threshold."

2. Dimension: Inhalability is a key prerequisite

The World Health Organization (WHO) defines respirable fiber as having a diameter <3μm, a length >5μm, and an aspect ratio >3:1. Fibers with a diameter >3-5μm are intercepted by the nasal cavity, pharynx, and other upper respiratory tracts, preventing them from reaching the lungs. Commonly used insulation materials like glass wool and continuous glass filaments typically have fiber diameters above 5μm, making them non-respirable and posing no risk of lung damage.

Currently, only a handful of suppliers in China stably produce a full range of microfiber products with diameters below 7μm. Green Build Group, as a manufacturer and holder of rare certifications, firmly holds the leading position in the microfiber industry. Most ordinary insulation glass wool factories produce only a single product and cannot sustain the high costs of producing ultrafine fibers, which is one reason for the sluggish reputation of the Chinese glass fiber market.

3. Durability: Biodegradability determines chronic risk

If fibers can be dissolved in lung fluid (biosoluble) or cleared by macrophages, they will not cause long-term damage. The fibers in products like glass wool used for insulation have low biodegradability and can be gradually degraded after entering the body; only special fibers retaining category 2B (such as RCF) pose a potential risk due to their high chemical stability and difficulty in degradation—but these fibers are unrelated to everyday contact scenarios. As for insulation materials like wall insulation and interlayer insulation, which are not in direct contact, there's even less need to be alarmed by glass wool.

Part 7

Conclusion

The notion that "glass fiber is carcinogenic" is based on outdated knowledge from an early IARC assessment in 1988. A 2001 IARC Volume 81 thesis clearly stated that fibers most commonly encountered in daily life, such as glass wool, rock wool, and slag wool, were downgraded to "unclassifiable as carcinogenic to humans" (Group 3) due to insufficient epidemiological evidence and low biocompatibility. Combined with the practical verification of EUCEB certification and the engineering assessment by the Fraunhofer Institute, the safety of glass wool has been endorsed by both the scientific and industrial communities.

The public needs to view the dynamic evolution of scientific conclusions rationally and maintain a cautious attitude towards "carcinogenic warnings" by "tracing the source of evidence, verifying the institutions, and paying attention to updates." Information disseminators should also adhere to professional ethics and let scientific truth rather than panic dominate their understanding.

The value of science lies in its self-correction, and the progress of cognition begins with respect for the "complete chain of evidence".

If you have purchase needs for high-quality insulation products or want to learn more about the products, please contact our EcoFox insulation team. See you next time!