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| The CD that broke while being gently cleaned and polished. |
Physical media collectors face a new threat as CDs are found cracking and shattering without warning
For years, collectors and archivists have worried about the slow degradation of optical media through bit rot and laser rot. Now, a more dramatic problem has emerged: some CDs and DVDs are literally cracking apart, sometimes shattering into multiple pieces despite showing no prior signs of damage.
The issue gained widespread attention when numerous optical-disc collectors on X (formerly Twitter) shared photos of discs that had split or broken unexpectedly. In many cases, the discs appeared to be in perfect condition until they suddenly failed.
According to discussions among collectors and preservation experts, the failures may stem from chemical reactions affecting the polycarbonate substrate — the plastic layer that forms the body of a CD. This isn't simply age-related deterioration; instead, the damage appears to be triggered by exposure to certain substances.
The Cleaning Solution Problem
In one notable case, a collector reported that a CD broke while being gently cleaned and polished. The damage was attributed to chemical cracking of the polycarbonate caused by a diluted cleaning solution. Rather than being gradual degradation, the chemicals weakened the plastic structure until it suddenly fractured.
This highlights a significant concern: even careful maintenance using standard cleaning products could potentially cause catastrophic failure if the chemicals are incompatible with the disc's materials.
The Foam Storage Hazard
Perhaps even more concerning is another case where a CD stored in a foam-padded protective case was found in multiple pieces. According to explanations offered by users familiar with materials science, some types of polyurethane foam release ammonia-containing compounds over time. In a sealed case, these substances can accumulate and potentially weaken, craze, or crack the polycarbonate substrate.
The exact causes remain uncertain, and the reported explanations are largely based on observations rather than controlled testing. It would be premature to conclude that cleaning products or foam padding are definitely responsible for every case. Nevertheless, the underlying chemistry is plausible.
Understanding the Science
Certain aggressive solvents, including acetone and benzene, are known to damage polycarbonate. Even prolonged exposure to less aggressive chemicals may contribute to cracking under specific conditions. The risk increases when discs are stored in sealed containers where fumes can concentrate over extended periods.
Interestingly, CDs may be particularly vulnerable because they rely on a single layer of polycarbonate. DVDs use two polycarbonate layers bonded together with adhesive, which makes them less susceptible to the specific type of substrate damage described in these cases.
The Growing List of Threats
As Tom's Hardware reported, this issue adds to the already extensive list of threats facing physical optical media:
- Bit rot and laser rot: The reflective layer degrades due to oxidation, contaminants, or UV exposure
- Adhesive separation: DVDs can experience delamination between their polycarbonate layers
- Chemical reactions: As now documented, certain substances can cause physical cracking
- Physical damage: Scratches, warping, and other mechanical issues
Implications for Collectors
The latest cases are particularly relevant to collectors of old games, software, music, and other digital archives. Optical discs are often kept for decades as backups or historical records, but their physical durability does not guarantee that the data will remain accessible indefinitely.
For those with valuable optical disc collections, the safest approach remains clear: don't rely on a single copy. Regular backups to multiple storage media, including hard drives and cloud storage, provide the best protection against both gradual degradation and catastrophic physical failure.
While the exact scope of this newly identified threat remains to be determined, it serves as yet another reminder that physical media, no matter how well preserved, requires active management and redundancy for long-term data preservation.
CDの劣化問題。
— 日本レトロゲーム協会 (@japanretrogame) August 6, 2026
通常通り優しく磨いていたのですが、
薄い氷のようにバリッと割れてしまいました。。
中々高価なソフトなので辛いです😭
数十年後にはCDゲームソフト、
みなこうなってしまうのでしょうか。。 pic.twitter.com/k4gMZWFrQt
CDの劣化が話題ですが、密閉度の高い精密機器収納用のトランクとか開けた時に、緩衝用のスポンジから臭い匂いがする事がありますよね？
— X68PRO-HD (@CZ662C) August 6, 2026
あれ大体がでアンモニアなので、専用ソフトインストール用のCD-ROMとか入れてそのまま蓋をしておくと、ポリカーボネート部が侵されてこうなります。 https://t.co/5eTX6wGWll pic.twitter.com/ibAgBcEOPx