The article considers various approaches to norms and deviations in translation from English into Latvian in the field of ecology and environment protection. Terms and professionalisms created as a result of various deviations in the English for special purposes are studied in contrastive perspective using the methods of lexico-semantic and pragmatic analysis in order to investigate whether these lexical items can be reproduced in translation of scientific and technical texts with a minimal loss of meaning. Linguistic deviations, which appear as a result of application of foregrounding strategies, cannot also be avoided for the reason that translators working with the lexical items in one language have to find if not completely identical then more or less functionally appropriate lexical items in the target language, in order to ensure their interlingual alignment. Thus, in translation of scientific and technical texts certain deviations from linguistic norms are acceptable because content precision is more important than linguistic accuracy.