Ron Canada has played several antagonistic characters in Star Trek - In Next Generation, he is the interpreter of the progenitor's intent in "The Masterpiece Society" - A rigid legalistic and religious Pharisee. In Deep Space Nine, he was a Klingon Arbiter prosecuting The Federation and particularly Worf.
In this Voyager offering, he is the Captain of a Malon Toxic Waste Disposal Ship which is suffering unexplained malfunctions and disasters. Of course, there is a reason why these things went wrong, but Voyager Members must needs to be sent into the middle of a Maelstrom of Theta Radiation to get to the Bottom of it.
To make Matters Worse, B'Elanna is having a Klingon Fit and is suffering the browbeating of Janeway, Chakotay and Tuvok- Tuvok tries to teach her some Vulcanian Brain-Meditation Techniques, to apparently No Avail.
Apparently, there is some kind of Malon Radiation-Monster which is attacking the Malon crew of Toxic Avengers, in fact, "it" kills off all of the Malons save Ron Canada and Lee Arenberg. Alexander Enberg steps away from his Voyager Vulcan role to play a 3rd Malon Engineer who gets melted by Radiation (You can only identify him by his Voice).
Mostly I liked this ep due to the interactions of Ron Canada and B'elanna. They want to kick each other's arses but they end up having a respect for each other, save for B'elanna giving the guy a Mouth Lashing at the end.
But the very thing which is causing B'elanna problems with the Voyager Crew is the one thing which saves her, Neelix and Ron Canada from being converted into Atomic vapour.
This episode also tells us more about the Malon culture, and that they have built a beautiful culture which can only exist by polluting the entire Delta Quadrant. But even Cultures who Irradiate their galactic Neighbors have Religious Golems. Find Out in this episode.