" Interior Department staff members said they had observed bubbles and small holes in one of the layers, indicating that the material might not be adhering as it should.
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The original plan was to use a robot to ensure the color would be applied consistently, but the contractor is now entrusting the job to individual workers instead, the documents indicate. That, the documents say, left different shades in different parts of the pool — and questions about what an uneven paint job might mean for the pool’s final appearance."

NYT