Benzaldehyde is the simplest and possibly the most industrially useful member of the family of aromatic aldehydes. Benzaldehyde exists in nature, primarily in combined forms such as a glycoside in almond, apricot, cherry, and peach seeds. The characteristic benzaldehyde odor of oil of bitter almond occurs because of trace amounts of free benzaldehyde formed by hydrolysis of the glycoside amygdalin. Benzaldehyde is a versatile intermediate because of its reactive aldehyde hydrogen, its carbonyl group, and the benzene ring. Benzaldehyde is formed from phenylpyruvic acid, derived by the aminotransferase activity on phenylalanine, in the presence of high levels of Mn2+, and contributes to the generation of flavor compound during cheese ripening. Benzaldehyde is a synthetic flavoring substance, sanctioned by the U.S. Food and Drug Administration (FDA) to be generally recognized as safe (GRAS) for foods. Benzaldehyde is also recognized as safe for use as a bee repellant in the harvesting of honey. Benzaldehyde's most important use is in organic synthesis, where it is the raw material utilized to produce various aldehydes. Because Benzaldehyde rapidly metabolizes to Benzoic Acid in the skin, the available dermal irritation and sensitization data demonstrating no adverse reactions to Benzoic Acid were considered supportive of the safety of Benzaldehyde.

Aniline is a toxic organic compound consisting of a phenyl group attached to an amino group. It is the prototypical aromatic amine. Aniline and its derivatives are very important for the synthesis of chemical products such as dyes, resins, and medicines. The main use of aniline is in the manufacture of precursors to polyurethane. Aniline is a carcinogen that is considered to induce tumors secondary to hemosiderosis as a consequence of methemoglobinemia. Aniline is classified as Group 3, not classifiable as to its carcinogenicity in humans (IARC, 480 1987b). Aniline occurs naturally in some foods (i.e., corn, grains, beans, and tea), but the larger source of exposure is in industrial settings. Lifetime permissible daily exposure (PDE) for aniline is 720 ug/day. Simple anilines such as aniline and monosubstituted anilines are known to disappear from the environment mainly via biodegradation.

Fentanyl is a potent agonist of mu opioid receptor. It is used to relieve severe pain, such as after surgery or during cancer treatment, and breakthrough pain (flare-ups of intense pain despite round-the-clock narcotic treatment). Fentanyl is an extremely powerful analgesic, 50–100-times more potent than morphine. Fentanyl harbors massive risk for addiction and abuse regardless of its prescription form. Fentanyl abuse is especially dangerous to those without a tolerance to opioids. The substance’s already elevated risk of overdose is multiplied when someone without a tolerance abuses it.

Fentanyl is a potent agonist of mu opioid receptor. It is used to relieve severe pain, such as after surgery or during cancer treatment, and breakthrough pain (flare-ups of intense pain despite round-the-clock narcotic treatment). Fentanyl is an extremely powerful analgesic, 50–100-times more potent than morphine. Fentanyl harbors massive risk for addiction and abuse regardless of its prescription form. Fentanyl abuse is especially dangerous to those without a tolerance to opioids. The substance’s already elevated risk of overdose is multiplied when someone without a tolerance abuses it.