The first correlation is positive, but it does not tell you anything. It is inevitable that a larger enterprise with a larger workforce will have a larger number of people with accidents.
The second correlation is actually a lot more informative. It suggests that larger enterprises are safer with a smaller accident rate.
If you look at your data this is what you see. An enterprise with just 10 employees has 3 accidents for an accident rate of 3/10 = 33%. That enterprise is a lot less safer than the second one which has 100 employees and only 100/15 = 15% accident rate.
In my mind, your first correlation is somewhat "wrong" because it does not scale the number of accidents by the number of employees. The second correlation is scaled and therefore much more informative.
One thing to watch out for is that none of your correlations are statistically significant because your sample size, just three data points, is way too small to overcome the small sample error syndrome.
To infer some more reliable conclusion, I suspect you would need at least 10 if not 20 companies of each size to derive any reliable assessment of the relative risk of working for companies of different size.
Watch out for qualitative factors, so that your companies are very similar. If you compare small companies of industrial scuba divers vs. large retailers, the small companies will look artificially riskier. You would have to compare small retailers vs. large retailers to get a better assessment.