Only a 40% allocation of originally contracted ethylene volumes will be available for June under the force majeure, the sources said.
Williams representatives were not immediately available to comment.
The explosion and fire at Geismar injured 73 and killed one person, Louisiana governor Bobby Jindal said in a late afternoon conference Thursday.
Spot ethylene prices pushed up even further in early morning trading. June spot bids were heard in the range of 58.50-59 cents/lb Mont Belvieu-Williams pipeline basis, against offers heard in the range of 62-64 cents/lb Mont Belvieu-Williams pipeline basis. Fourth-quarter deals were heard at 56 cents/lb Mont Belvieu-Williams pipeline basis.
Platts assessed spot ethylene Thursday at 57.75-58.25 cents/lb FD USG, itself a 5-cent/lb increase from Wednesday.