If you do value your hearing, then either invest in noise-cancelling headphones or lower the volume.
Noise-cancelling equipment prevents you from having to compensate for ambient noise with a higher volume level, theoretically allowing you to enjoy your music at a lower real volume.
Apparently even IEMs (in-ear-monitors) may increase sound pressure by up to around 10dB (compared to supra/circumaural headphones) - so the ideal solution is to get noise-cancelling studio headphones. However, whilst this will put you in a position to prevent hearing damage, you're still responsible for listening at a safe volume with the equipment. On the downside, noise-cancelling headphones generally don't sound anywhere near as good as open ones (but very good IEMs will offer you possibly the best sound).