There may still be some laboratory environments where the provided personal protection equipment does not protect wearers of contact lenses, and they will remain banned. There are three major areas of concern about the hazards of wearing contact lenses in chemical laboratories. They can hold particulate or liquid material against the cornea. The modern soft contact lenses are considered suitable for most environments, except where heavily contaminated with metal particles. Hard contact lenses are not considered suitable for use in particle-contaminated areas.
Contact lenses can be difficult to remove after a chemical splash.
This is a concern, and is one reason why wearers of contact lenses in laboratories should be obviously identifiable to first-aid and professional secondary care providers. Contact lenses may absorb and retain chemical vapours. This effect was not observed in the splash experiments above, and soft lenses have been shown to reduce the effect of acids, perhaps because tears can dilute the acid by the time it passes through the lens. Some chemical vapours may be absorbed and retained, but often exposure should be eliminated by personal protection equipment anyway.