A massive, billowing cloud of black smoke that poured into the air above Hovensa refinery on St. Croix Thursday morning was a controlled flare of oil diverted from a broken processing unit, according to refinery officials. (For video of the oil flare and a further update, see story’s end.)
Construction workers near the refinery say the plume of black smoke was billowing when they arrived at 7 a.m.
Hovensa spokesman Alex Moorhead said a processing unit began having problems, and around 6:55 a.m. the refinery diverted heavy oil away from the unit to a ground flare system for burning while the problem was fixed. By 11 a.m., the smoke had died back to nearly nothing.
"Unfortunately, burning the oil produced the black smoke," Moorhead said. No one was injured when the processing unit failed or during the burning of the diverted oil, according to Moorhead.
The oil could not simply be shut off, Moorhead said, because it the oil has to be brought up to temperature and down from temperature gradually, or else the sudden temperature changes will wreak havoc with the machinery and cause further problems.
The oil was diverted to a ground-level flare system, surrounded by earthen berms. "Imagine a set of really large gas burners like those on your stove," Moorhead said, describing the system.
Despite the size and darkness of the smoke cloud, Moorhead said Hovensa’s air quality monitoring found no substances in the air "exceeding the standard established by the U.S. Environmental Protection Agency." The refinery reported the situation and smoke plume to 911, VITEMA, the V.I. Port Authority, and the Federal Aviation Administration Control Tower at the Henry E. Rohlson Airport, according to Moorhead.
The V.I. Department of Planning and Natural Resources is onsite at the refinery and its Division of Environmental Protections’ Air Pollution Control Program is conducting air monitoring, according to a DPNR statement.
Its preliminary investigation indicates a high amount of hydrocarbons burning in the ground flare, which made the smoke thick and opaque.
The U.S. EPA has also been notified and is sending a monitoring team from Puerto Rico today, according to DPNR.
As a precaution in case any material in the air might fall out onto resident’s roofs, DPNR is urging residents and businesses in the affected areas to immediately disconnect downspouts from their cistern to protect the cistern water.
Young children, older persons and persons with respiratory ailments such as allergies, lung disease, and asthma should consider staying indoors or relocating to areas less affected.
For more information on air quality, contact the Division of Environmental Protection at 774-3320 in St. Thomas and 773-1082 in St. Croix.
Update at 6:20 p.m.: DPNR officials are presently investigating incident-related activities and reports of oil spots on vehicles at the Containerport facility and at Rohlsen Airport, according to a DPNR statement. DPNR Commissioner Mathes has directed Hovensa to continue its damage assessment to neighboring communities and implementation of immediate remediation efforts.