JEFFERSON CITY, Mo. (AP) — Missouri State Parks officials on Friday said they can't verify that solar eclipse glasses and viewers the agency sold across the state meet safety standards and are warning people not to use them when viewing Monday's eclipse.

Renee Bungart, spokeswoman for the Department of Natural Resources, which oversees Missouri State Parks, said it's unclear how many of the PMS Promo Mart glasses and viewers were sold, but the agency purchased 25,000. Those who bought that type of eclipse eyewear from parks and historic sites can return them for a full refund.

"Missouri State Parks apologizes for any inconvenience this may cause but we want to take all possible steps to make sure everyone can safely view the solar eclipse," Missouri State Parks Director Ben Ellis said in a statement.

Bungart said the agency ordered eclipse eyewear last year and received documentation that it met certification. She said the current issue stems from an Aug. 8 shipment of PMS Promo Mart glasses and viewers.

Staff noticed differences between the two shipments Tuesday, when a worker reported some glasses from the latest shipment were damaged. Bungart said officials asked for proof by Wednesday that the recent shipment met safety standards, but a vendor working with the state didn't provide it. Parks and historic sites were told to stop selling PMS Promo Mart goods on Wednesday, she added.

Ellis said the advisory is "a precautionary measure, because we cannot verify that the solar eclipse glasses and viewers meet all the requirements to safely view the eclipse."

Bungart said there's still eyewear from the initial shipment available at some parks, and she said officials are confident those Eclipse Shades glasses from Rainbow Symphony meet safety standards.

Doctors around the U.S. launched campaigns this summer to warn people that they can damage their eyes staring directly at the sun. NASA, the American Astronomical Society and others are urging eclipse watchers to stick with reputable makers of sun-gazing devices out of concern about potentially dangerous knockoffs. The society's solar eclipse task force has put out a list of approved manufacturers, which include Rainbow Symphony.