Malachite green (LMG) is used as a detection method for latent blood in forensic science. Hemoglobin catalyzes the reaction between LMG and hydrogen peroxide, converting the colorless LMG into malachite green. Therefore, the appearance of a green color indicates the presence of blood. In 1992, Canadian authorities determined that eating fish contaminated with malachite green posed a significant health risk. Malachite green was classified a Class II Health Hazard. Due to its low manufacturing cost, malachite green is still used in certain countries with less restrictive laws for non aquaculture purposes. In 2005, analysts in Hong Kong found traces of malachite green
Italian submarine Malachite Crete, "Malachite" sighted a British cruiser escorted by a destroyer. She launched two torpedoes at the target, but they both missed her by the stern. From 3 to 14 July 1941 she patrolled north of Ras Azzaz. At 20:00 on July 3 "Malachite" sighted a large cruiser (possibly ) escorted by two destroyers, and immediately launched a torpedo. There was an explosion heard, but there is no reports of this attack in British post-war documents, although some believe an escort was hit. From September 25 to October 5 1941 she patrolled off Ras Aamer. From January 20 to 27, 1942