Translation guide
The English word 'hazardous' describes something that is dangerous or risky, often in a formal or technical context. In Japanese, the most common equivalent is 危険な (kiken na), but other expressions exist depending on the nuance: physical danger, health risks, or figurative risk.
To describe something that poses a danger or risk, in a general sense.
The most common and versatile adjective meaning 'dangerous' or 'hazardous'. It can be used for physical dangers, health risks, and figurative risks.
この道は夜は危険です。
This road is hazardous at night.
hazardous chemicals
Means 'harmful' or 'toxic', often used for substances or environments that are hazardous to health.
有害なガスが発生した。
Hazardous gas was emitted.
A more casual adjective meaning 'dangerous'. It can be used in everyday conversation but is less formal than 危険な.
そんなことをするのは危ないよ。
It's hazardous to do that.
Specifically referring to substances, materials, or conditions that are harmful to human health.
A phrase meaning 'harmful to health'. It is commonly used in warnings and product labels.
この製品は健康に有害な物質を含んでいます。
This product contains substances hazardous to health.
Means 'toxic' or 'poisonous', emphasizing the presence of poison. Used for chemicals, plants, etc.
毒性のあるキノコに注意してください。
Be careful of hazardous mushrooms.
Describing weather, road conditions, or environmental situations that are dangerous.
Literally 'dangerous condition', used in formal warnings about weather, roads, etc.
大雪のため、道路は危険な状態です。
Due to heavy snow, road conditions are hazardous.
Means 'stormy weather' or 'rough weather', often used in forecasts to indicate hazardous conditions.
荒天のため、飛行機が欠航になった。
Flights were canceled due to hazardous weather.
Used metaphorically to describe a plan, investment, or action that is risky.
The same 危険な can be used figuratively for risky ventures.
それは危険な賭けだ。
That's a hazardous gamble.
Means 'high-risk', often used in business or investment contexts.
リスクの高い投資は避けるべきだ。
You should avoid hazardous investments.