He's a police officer. He should have know better.
He also should have been aware of what would happen when the blood was drawn. Did he think it was for DNA?

Was he unaware of procedure?

Wouldn't it be unlawful for a police department to draw blood from an officer and keep the findings within the department? When the department finds drugs in your blood, doesn't it become a criminal matter? Sadly there was an accident involved. He should suffer the same consequences as anybody else when getting caught driving under the influence. Having a badge is not immunity from the laws.
Total Bullshit!