adjective

causing or likely to cause harm.

the ozone layer blocks the harmful rays from the sun

damaging,injurious,detrimental,dangerous,deleterious,unfavourable,negative,disadvantageous,unhealthy,unwholesome,hurtful,baleful,wounding,destructive,environmentally unfriendly,noxious,hazardous,poisonous,toxic,deadly,lethal,bad,evil,malign,malignant,malevolent,corrupting,subversive,pernicious,baneful,maleficent,malefic