It is not possible to pass environment variable values containing quotes, e.g.

[program:x]
command=bash -c export
environment=MYSQL_PW="5ny6{wo'\"7n"

throws

ERROR: CANT_REREAD: No closing quotation

Currently shlex is used in legacy mode to parse the env settings, which does not allow any kind of escaping and also has some other odd edge cases (http://docs.python.org/2/library/shlex.html#parsing-rules). I'd propose switching the lexer to posix mode. Ideally, we would like to be able to dump any string dictionary and have it load correctly as environment for the process.