Drano can be made into a bomb with only the addition of a few household items. These bombs are mixed in a soft drink plastic bottle and once mixed up will explode in about 30 seconds. They are similar to bombs made with dry ice. While they are unlikely to do much damage or injury they could if they were set off in the right place of if someone were handling them as they exploded.
Getting a call of Drano bombs is unlikely to result in officer injury unless you arrive almost immediately or if the suspect is still actively setting them up when you arrive. They are quick and easy to make so it is possible they could be there when you investigate. The important thing to note is the person placing the device will be close by when they explode due to the short time it takes for the chemical reaction.
This means as you approach you need to be especially aware of people leaving or near the scene who may be involved in the incident. High school or college age males would be typical suspects; playing a prank or simply engaging in risky behavior are typical of the type of suspect that may use this type of bomb. Certainly anyone with Drano and aluminum foil without much of an explanation would be suspicious of this type of activity; that’s what the SGT Says.