This seems to be a question of clearly ascribing meaning to the function of an object or system with an associated value judgement regarding the use of the object or system. To start with, you should try to avoid using words that ascribe connotations of ethical or moral value directly to inanimate objects, if possible.
Moving on, in civil engineering we often use the term 'released' rather than 'emit,' because it is succinct, unambiguous and relatively untainted in terms of subjective connotations, though 'emit' works, too.
So, as an alternative: 'It released harmful chemicals into the environment.'
Perfectly functional statement.
As a simple alternative, you could say: 'It released pollutants into the environment."
If you want your reader to see both 'harmful chemicals' and a form of the word 'pollution' in the sentence, you could say: 'It released pollutants with harmful chemicals into the environment."
Hope that helps.