Is "inactivate" really a word?

At my business most of the employees use the word inactivate frequently. Is this proper grammar? I've always used deactivate.

There are 88 examples of inactivate in the Corpus of Contemporary American English and 102 for deactivate, showing they occur with about equal frequency. Most of the examples for inactivate, though, are used in a biological context, talking about inactivating viruses, genes, and “potent mutagenic compounds”, for example. So inactivate appears to be a term of art in the science of biology.

According to OneLook, it is a word in 25 dictionaries:

http://www.onelook.com/?w=inactivate

• verb: make inactive
• verb: release from military service or remove from the active list of military service

The New Oxford American Dictionary reports just an example of sentence with inactivate.

inactivate ɪnˈæktəˌveɪt/
verb [transitive]
make inactive or inoperative: household bleach does not inactivate the virus | [as adjective] (inactivated) an inactivated polio vaccine.

Outside that context, I have never heard somebody using that verb.