They are GINA gaskets[0], they were supposed to last 120 years[1], but it has recently been shown that they may deteriorate faster than previously expected due

They are GINA gaskets[0], they were supposed to last 120 years[1], but it has recently been shown that they may deteriorate faster than previously expected due to being under constant compression[2][3] [0] https://www.trelleborg.com/en/marine-and-infrastructure/media/in-the-news/tailor-made-sealing-systems-for-the-fehmarnbelt-immersed-tunnel https://www.trelleborg.com/en/marine-and-infrastructure/medi... [1] https://www.trelleborg.com/marine-and-infrastructure/-/media/marine-systems/resources/case-studies/downloads/keeping-immersed-tunnels-watertight-for-120-years.pdf?rev=30fcb4a6a6f04555afe7c96290dae4ab https://www.trelleborg.com/marine-and-infrastructure/-/media... [2] https://www.sciencedirect.com/science/article/abs/pii/S0886779825008909 https://www.sciencedirect.com/science/article/abs/pii/S08867... [3] https://dailygalaxy.com/2026/03/rubber-used-in-undersea-tunnels-decay-fast/ https://dailygalaxy.com/2026/03/rubber-used-in-undersea-tunn...