Venezuela's Amuay and Cardon refineries, which make up the giant 940,000 barrel per day (bpd) Paraguana refinery, suffered accidents that left a total of five injured, official sources and traders said on Thursday.
Traders said an explosion hit the alkylation unit of the 300,000 bpd Cardon refinery on Wednesday, though state oil company PDVSA did not immediately confirm the accident.
One trader and a local radio station reported that the incident had left three injured.
PDVSA on Thursday issued a press release describing an accident at the 640,000 bpd Amuay refinery in which two workers were burned by hot oil while carrying out maintenance on the refinery's delayed coker unit.
Refinery operations were not affected by the incident, and the workers were reported to be in stable condition at a nearby hospital.
The press release did not specify the date of the Amuay accident, but traders said it happened late Tuesday night or early Wednesday morning.
Some gasoline traders in the New York Harbor market pegged the gasoline imports from Venezuela at about 80,000 tonnes or 500,000 barrels so far in July.
Venezuelan gasoline exports to the United States have been erratic since last year due to consistent operational problems at the refineries.
US April imports of finished gasoline product from Venezuela were pegged at 240,000 barrrels, compared with 957,000 barrels in March, according to latest data issued by the Energy Information Agency. April imports of gasoline blending components dropped to 1.58 million barrels from 3.19 million barrels.
Cash conventional regular gasoline for prompt loading in the New York Harbor dropped by about 2 cents a gallon from a week ago to a discount of 5 cents per gallon under the Nymex quotes.
Venezuela is the world's fifth-largest oil exporter and supplies around 12 percent of total US oil imports.