BP oil spill workers in the Gulf of Mexico prepared for a possible evacuation on Thursday as a brewing tropical storm threatened more delays in efforts to end the environmental disaster.


Some oil-skimming ships came ashore as Gulf seas grew choppy and U.S. officials evaluated the threat from a tropical storm forming in the Caribbean near the Bahamas. The storm is projected to swirl across the Gulf near the site where crews are working to plug the spill.


Ships collecting seismic and acoustic data on the capped well and two rigs drilling a pair of relief wells remain on the site, but an evacuation would bring a temporary halt to both operations.


“There has been no evacuation of equipment, but that could change. Some skimmers have been coming in,” said a command center spokeswoman.


BP evacuated nonessential workers from eight operated offshore Gulf facilities, but the evacuations did not affect operations at the spill, the company said in a statement.

An evacuation at spill sites could force a delay of 10 to 14 days in operations, retired Coast Guard Adm. Thad Allen said on Wednesday. Ships in the region need several days to disengage from the operation and head to safety.