恐（おそ）れがある is a set phrase in Japanese that is used in a fairly literal sense to convey that 'there is a chance of (A)', or 'there is a fear of (A)'. This is a combination of the noun, 恐（おそ）れ 'fear', が, and the う-Verb ある 'to be'.
恐（おそ）れがある will be used when (A) is a negative outcome that may potentially occur in some particular situation, and is usually used to warn about being careful of something.
恐（おそ）れ is primarily used directly after verbs, or nouns followed by の.
高温（こうおん）にすると爆発（ばくはつ）する恐（おそ）れがあるので、直射（ちょくしゃ）日光（にっこう）が当（あ）たるところに置（お）かないでください。
Since there is a possibility of explosion when this reaches high temperatures, please don't place this in direct sunlight.
津波（つなみ）の恐（おそ）れがある場合（ばあい）には、速（すみ）やかに避難所（ひなんじょ）まで避難（ひなん）してください。
When there is a risk of a tsunami, please evacuate to the evacuation area.
In most cases, 恐（おそ）れ carries the meaning of something that innately carries some kind of concern in relation to it, so depending on the context, alternative suitable translations could be 'concern', 'anxiety', 'worry', etc.
Fun-fact - In addition to がある following 恐（おそ）れ, other common combinations are
恐（おそ）れを抱（だ）く 'to carry the fear of (A)', or 'to bear the fear of (A)', and
恐（おそ）れが強（つよ）まる 'for the fear of (A) to strengthen', or 'for the fear of (A) to intensify'.
若者（わかもの）が将来（しょうらい）について恐（おそ）れを抱（だ）くことは普通（ふつう）のことです。
It is normal for young people to have fears about the future.
夏場（なつば）の現場（げんば）では熱中症（ねっちゅうしょう）の恐（おそ）れが強（つよ）まるので、作業員（さぎょういん）の方（かた）はこまめに水分補給（すいぶんほきゅう）と休憩（きゅうけい）を取（と）るようにしてください。
Workers are encouraged to hydrate and take frequent breaks, as the risk of heat stroke increases at construction sites during summer.