Why are fireworks illegal in Oregon?

Why are Large fireworks illegal in Oregon? It's all just wimpy kiddo fireworks that you can buy. I'm staying a few nights in Portland and they seem to be real anal about large fireworks. My friends neighbor got fined over $2700, for setting off large fireworks and I guess the cops found a lot more fireworks in his house. The only fireworks that are legal in Oregon are wimpy little sparkler type of fireworks. It almost seems Un-American to me. during independence day they probably set off large fireworks, not some wimpy ground fireworks.