general contractor liability for employees of subcontractor
roofing
fall protection
leading edge
training by competent person in fall hazards
safety shoes
personal protective equipment
29 CFR § 1926.28(a)
29 CFR § 1926.501(b)(2)(i)
29 CFR § 1926.502(a)(2)
29 CFR § 1926.503(a)(2)
29 CFR § 1926.503(b)(1)