(CBS SF) — An environmental group has issued a warning about kids’ Halloween costumes and trick-or-treat bags found with what the group claims are elevated levels of toxic chemicals.

A study by the Michigan-based Ecology Center’s HealthyStuff.org project looked at more than 100 Halloween costumes and accessories sold at retailers such as Walmart, Target, CVS and other stores.

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Finding showed many of the items had high levels of chemicals like lead, arsenic, flame retardants and chlorine; substances which are linked to asthma, birth defects, learning disabilities, reproductive problems, liver toxicity and cancer.

According to the study:

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  • Five percent of the items had lead levels higher than the 100 parts per million standard for children’s products, and one item – Toddler Batman Muscle Costume purchased at Walmart – also had both high lead and tested positive for a phthalates banned for use in children’s products.
  • Ten percent of the items had high levels of bromine, a flame retardant. Among them were Disney “Cars” and “Princess” trick-or-treat bags from Kroger and Halloween light sets from Walgreens and CVS.
  • Thirty-nine percent contained tin at levels suggesting organotin stabilizers which can be endocrine disruptors or impact the developing brain and damage the immune system. Among them were plastic dress-up shoes and a skeleton light stick.

The Ecology Center said it was releasing its study in conjunction with a new national campaign urging major retailers to eliminate chemicals in consumer products and calling for reforms to federal chemical legislation.

CVS spokesman Mike DeAngelis told CBS San Francisco his company is committed to ensuring products sold are safe and of high quality, and that the company would review the report in question.

Walmart issued a statement saying:  “We take the issue of product safety very seriously. Standard testing procedures are in place for our products to assure compliance with all regulatory requirements and give customers trust in the quality and safety of items on our shelves. We are reviewing this matter further with our suppliers and will perform additional testing if necessary to help ensure items meet applicable requirements.”

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Other inquiries to Kroger, Target, and Walgreens were not immediately returned.