There are long-term health dangers too. Benzene, in particular, has been tied to adult leukemia and other cancers. Benzene does this by entering cells and damaging DNA material, Woodruff said, although the specifics are not well understood.
What makes crude oil potentially even more dangerous, however, is that it contains so many toxic chemicals that can all attack the body at once, Woodruff explained.
"The combination can, in many cases, have more effect," Woodruff said. "It's like getting hit from different sides -- right hook, left hook and on top of the head."
This sort of multiple attack is less well understood, as most studies tend to focus on one chemical at a time.
Another variable is how differently the toxins can affect different sorts of people.
"It definitely would be worse for children to be exposed," said Woodruff. Infants and even unborn children could also be seriously harmed because the neurotoxins can interfere with brain development, she said.
Many of the toxins in crude oil can be absorbed directly through the skin or lungs, so the only way to avoid them is to keep away or wear protective gear like specially-designed respirators, boots, gloves and suits.