Short-term loss of memory is not a sign of having been exposed to a hazardous chemical. However, damage to the nervous system might present as nervousness, irritability, sleeplessness, and may be signs of long-term exposure to a toxic chemical. 

Sneezing, coughing, sore throat can be signs of short-term exposure. Itching or a rash that develops and other symptoms like red and watery eyes can be examples of an acute reaction occurring soon after exposure.