How to locate and count the number of words in a column

So want to count the occurrences of contaminants but some cases has more than one contaminants so when I use the value_counts it counts them as one. For example "Gasoline, Diesel = 8" How would I count the them as separate without doing it manually.

And would it be possible to create a function that would make it easier to categorize them into lets say 4 types of contaminant? I just need a clue or a simple explanation on what I need to do.

data=pd.read_csv('Data gathered.csv') data

data['CONTAMINANTS'].value_counts().plot(kind = 'barh').invert_yaxis()