Who is the largest PVC manufacturer in USA?

Can you please provide some insight into the identity of the largest PVC manufacturer operating within the United States? I'm particularly interested in knowing which company holds the top position in terms of production capacity, market share, or any other relevant metrics that could help identify them as the industry leader. I understand that the PVC manufacturing landscape in the USA is diverse and competitive, so it would be greatly appreciated if you could shine some light on this particular question.