Technical Writting for commercial inspections

[JanetAC]

Hi! I write technical reports regarding environmental site inspections. When we discuss our site (the property) in the report we identify features that are on site and discuss them. I have been told in the past there are three ways to use the term on site:
1. on site (my way)
2. on-site
3. onsite
As long as it is uses consistently throughout the document it is correct. For example you can't say on site in a previous section then say on-site later. Recently someone higher up has said that the way I spell on site is wrong and to stop using it. I don't believe this is right and as long as I keep on saying "on site" consistently I'm correct. Any input would be appreciated.
Thanks

[Tdol]

It depends on the usage to me- if t is being used as an adjective, I would hyphenate:
An on-site problem.
However, if you're using it as a prepositional phrase, then I would keep them as separate words.