This is from ingestion of coal tar products: cresol, creosote, pitch as found in tar paper, treated wood, disinfectants, etc.
Death may be the first symptom. Otherwise, signs may be those typical of chronic liver disease: icterus (yellowing of skin and whites of eyes), ascites (abdominal swelling), anemia.
Don’t let animals consume treated wood. Be careful about what happens to scraps of tar paper left over from building projects. Old buildings should be removed if they are in a state of collapse or severe disrepair where animals have access to tar paper from walls or roofs. Clay pigeons (which may contain tar) should always be removed.
An alertness to whatever animals can chew on is absolutely essential.