Ключевые слова: bag, biological, chemical, clean, cleaning, crisis, crossbones, danger, death, disaster, ecological, ecologist, ecology, environment, environmentalist, garbage, gas, grass, hazard, human, male, man, mask, nature, people, person, picking up, plastic, poison, pollution, problem, protection, protective, radiation, recycling, refuse, researcher, rubbish, safety, sign, skull, suit, symbol, threat, toxic, trash, up, volunteer, warning, waste,