It wasn't the death of an employee that caused the closing of the sawmill, which, btw, was closed down in November 2000, not in "the late 1990's". The Martin Timber Company, which owned the sawmill, decided to get out of the sawmill business in the early 90's and double down on OSB and plywood and sold all three of their traditional softwood construction timber sawmills to Hunt Plywood in order to get funds to expand their OSB business. Hunt operated the plant for a short amount of time then closed it down in order to reduce competition for their sawmills elsewhere. Hunt removed most of the equipment and, combined with the railroad washing out, which meant that it became more expensive to ship out lumber, it simply wasn't economically viable to re-open the plant even if the Page Brothers, who operated the neighboring hardwood sawmill, had been able to come up with the funds to buy the sawmill from Hunt.

I am attempting to find sources for the above but I am related to the Page Brothers (in fact one of them leases my land in Castor right now) and was there first-hand to witness it, as well as being there when the flood washed out the railroad (and washed out three of the four roads leading out of Castor, that was exciting!). Wish me luck finding the documentation of what I saw with my own two eyes at the time.

Update: Found a cache of the AP story of the plant closing in 2000 and updated the main article to reflect its contents. Sadly, some reporter diving in from outside just doesn't pick up all the nuance (and really doesn't care, he's paid by the word, not by the fact). Oh well.