Oiling Pathologies

In addition to severe impacts on an animal’s ability to float and stay warm, petroleum compounds can impact oiled wildlife, including sea otters, in many other ways. These effects are best summarized by organ system.

Before reading the list below, see how many effects of oil on animals you can think of! These are the things to be watching for when performing a physical examination at intake, and while providing care for oiled sea otters.

Skin/ fur:

  • Inability to thermoregulate (animal easily gets too cold or too hot)
  • Matted coat and chemically- and physically-impaired hair quality
  • Compromised buoyancy (especially important for sea otter pups)
  • Skin burns, ulcers, necrosis (tissue death)
  • Skin rash/ sensitization
  • Secondary bacterial or fungal infections

General/ animal physiology and metabolism:

  • Markedly elevated metabolic rate/ nutritional requirments
  • Systemic toxicity of ingested oil
  • Dehydration
  • Severe nutritional stress and rapid weight loss
  • Severe social stress and abrupt territorial shifts/ Fight-associated trauma
  • Decreased availability of non-contaminated prey/ Forced, rapid prey shifts
  • Adapting to new and unfamiliar food items while hospitalized
  • Disrupted feeding patterns and diurnal cycles
  • Rapid mobilization of persistent organic pollutant burdens in adipose stores
  • Reactions to medications administered during care
  • Physiological stress of adaptation to freshwater pool system for immediate post-wash recovery


  • Corneal burns, ulcers or scratches/Corneal perforation or rupture/ Blindness/ Secondary infections

Respiratory system:

  • Obstruction of the nose or airways by petroleum compounds (asphyxiation)
  • Tissue burns/ chemical damage, leading to chemical pneumonia
  • Collapse of lung tissue (atelectasis)/ Impaired breathing
  • Air trapping in lung tissue (emphysema), formation of large air pockets in the lung (bullae)
  • Rupture of lung air pockets into the chest cavity (pneumothorax), leading to problems with breathing (dyspnea)
  • Reduced gas exchange with increased blood CO2 (hypercapnea) and decreased O2 (hypoxia)
  • Secondary bacterial, fungal or viral infections

Cardiovascular system:

  • Direct toxicity of absorbed compounds to cardiac muscle and blood vessel lining cells
  • Acute decompensation of pre-existing cardiac disease (cardiomyopathy)

Gastrointestinal/ hepatic:

  • Acute, severe anorexia
  • Oral, esophageal, gastric or intestinal ulcers (primary or due to stress/ infection)
  • Gastroenteritis and diarrhea/ Intestinal malabsorbtion
  • Death of cells lining the GI tract (mucosal necrosis)
  • Loss of appetite (anorexia)/ Gastrointestinal bleeding (primary or due to stress)
  • Secondary bacterial, fungal or viral infections

Liver/ Pancreas:

  • Hepatotoxicity/ hepatic necrosis
  • Decreased production of critical liver proteins (albumen, clotting factors, etc.)
  • Abnormal bleeding or clotting
  • Pancreatitis/ pancreatic necrosis


  • Nephrotoxicity/ Renal tubular necrosis/ Renal failure due to dehydration and muscle damage
  • Possible kidney cancer (In humans following sustained gasoline exposure)

Reproductive system:

  • Decreased sperm counts / Decreased fertility
  • Early embryonic death/ Fetal malformation/ Abortion
  • Decreased ability to provide adequate maternal care

Nervous system:

  • Neurotoxicity (especially the more volatile fractions: Benzene, toluene, xylene)
  • n-hexane exposure in humans: Numbness of feet and legs or paralysis (peripheral neuropathy)
  • Brain tumors (Humans with sustained petroleum exposure)

Endocrine system:

  • Adrenal gland: Cortical hypertrophy or necrosis/ Adrenal insufficiency
  • Thyroid gland: Linked with thyroid cancer (human petroleum workers)

Blood and bone marrow:

  • Anemia (Aplastic anemia in humans following sustained benzene exposure)
  • Bone marrow cancer (In humans, especially following sustained benzene exposure)

Immune system:

  • Immune cell lysis (lymph nodes, thymus, spleen, GALT):  Sustained stress and toxic petroleum compounds
  • Gastrointestinal tract colonization by opportunistic / antibiotic-resistant bacteria (especially if on antibiotics)
  • Enhanced disease susceptibility/ Worsening of pre-existing disease
  • Enhanced severity of infection by opportunistic pathogens (eg bacteria, parasites and viruses)
  • Reactivation/ recrudescence of chronic pathogens (eg herpesviruses and Toxoplasma)
  • Opportunistic infection of petroleum-induced lesions/ Increased fecal shedding of opportunistic bacteria
  • Enhanced potential for pathogen transfer between animals, and between animals and humans

Musculoskeletal system:

  • Struggling/ muscle damage (exertional myopathy)
  • Trauma/ decreased ability to avoid hazards
  • Significant risk of opportunistic bacterial infection (eg Strep phocae) if breaks in the skin

Chronic/ postexposure effects:

  • Damage to DNA or mitochondria
  • Many petroleum compounds act as tumor promoters (In humans: leukemia, thyroid, pancreas, bone and connective tissue tumors)
  • Chronic damage to the eyes, skin, cardiac or respiratory reproductive, immune and endocrine systems