However, some facility types, especially wrecking/ salvage yards, remain a challenge in terms of improving operations to protect water quality.
(some facility types; especially wrecking; salvage yards) (some facility types, especially wrecking/ salvage yards; remain; a challenge in terms of improving operations)
some facility types some facility types, especially wrecking/ salvage yards
especially wrecking remain
salvage yards
a challenge in terms of improving operations