Two incidents involving “exploding homemade devices” has caused the Boulder County Sheriff to warn county residents to be on the lookout for suspicious containers.

The most recent incident occurred late Monday night when a resident in the 7800 block of Durham Way in the Heatherwood subdivision reported hearing an explosion.

Tuesday morning, a ruptured plastic bottle with its lid intact was found near the location of the explosion reported at 11:30 p.m. Tuesday.

The sheriff’s office said that the bottle had been ruptured from some type of an explosion.

An additional search of the subdivision by sheriff’s deputies failed to find any additional devices.

Sheriff’s Commander Rick Brough said that at 8 p.m. on July 1, a plastic bottle was thrown from a black Chevrolet pickup at the intersection of Pawnee and Longview Drive in the Morton Heights subdivision in Niwot.

When a witness kicked the bottle, it exploded, said Brough. Neither the person kicking the bottle nor a second person standing nearby were injured.

Brough said the bottle contained chemicals that when combined created an explosion.

Brough said the Boulder Sheriff’s Office is warning the public of the two incidents because of the dangers involved.

In both Monday night’s incident, and the one in July, the devices were 12-16 ounce capped plastic bottles that contained a liquid chemical and aluminum foil.

Citizens are being cautioned against picking up suspicious containers that are found in their mailboxes, the street or on their lawns.

Such containers should not be touched and reported to the sheriff’s office.

Investigators are asking that anyone with information about the incidents call Northern Colorado Crime Stoppers at 1-800-222-8477.

Howard Pankratz: 303-954-1939 or hpankratz@denverpost.com.