Ключевые слова: alert, attention, beware, biohazard, biological, chemical, contamination, crisis, danger, dangerous, disaster, ecological, ecology, environment, environmental, field, forbidden, garbage, harmful, hazard, hazardous, nature, outdoors, outside, pictogram, plastic, poisonous, polluted, pollution, precaution, problem, radiation, radioactive, recycling, refuse, risk, rubbish, sign, signal, symbol, threat, toxic, toxin, trash, triangle, viral, warn, warning, waste, zone,