A resurfaced cycle path between Hastings and Bexhill had to be closed off shortly after reopening as the recycled material used contained broken glass.
The quarter-mile section at Bulverhythe was surfaced in recycled tarmac.
Cyclists contacted the Observer to vent their fury after the discovery was made.
Highways bosses have since apologised and undertaken further repairs.
One said: “Every bit of the new surface contained sharp pieces of broken bottles.”
The cyclist, who wished not to be named, added there was a ‘real risk’ of punctures and dogs were in danger of injuries.
He said: “This has always been the worst section of National Cycle Route 2.
“Even before the ‘improvement’ cyclists were avoiding this portion, and instead diverting along the busy and dangerous A259 between Bo-Peep and Ravenside Retail Park.”
Tony Harris said: “In the 50 years I’ve been a cyclist I’ve seen some things, but making a cycle path from material that contains broken glass is by far the most fantastically insane.
“But this is what happened between Galley Hill and the footbridge by the rail repair sheds.
“At first I thought that some vandal must have broken a bottle. But no, it was actually In the material for 300 metres.”
An East Sussex Highways spokesman said: “Our contractors completed resurfacing work on the Bulverhythe cycle path on Monday, July 3. The material used to replenish the path was a recycled product.
“On inspecting the completed work, engineers became aware of fragments of glass on the surface of the cycleway, and the path was subsequently closed so that further works could be undertaken to remove the glass fragments on the surface.
“The path was open for public use on Friday, July 14.
“We’d like to apologise to cyclists for any inconvenience caused while these works were carried out.”
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